E类业余无线电台操作证书考试题库 (共602道)

E1A01. Why is it not legal to transmit a 3 kHz bandwidth USB signal with a carrier frequency of 14.348 MHz? 为什么传输载波频率为14.348 MHz的3 kHz带宽USB信号是不合法的？

1. USB is not used on 20-meter phone 20米手机未使用USB
2. The lower 1 kHz of the signal is outside the 20-meter band 信号的低1 kHz在20米波段之外
3. 14.348 MHz is outside the 20-meter band 14.348 MHz在20米波段之外
4. The upper 1 kHz of the signal is outside the 20-meter band 信号的上1 kHz在20米波段之外

E1A02. When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band? 当使用显示电话信号载波频率的收发器时，以下显示的频率中的哪一个表示适当调整的LSB发射将完全在频带内的最低频率？

1. The exact lower band edge 确切的下带边缘
2. 300 Hz above the lower band edge 低频带边缘以上300 Hz
3. 1 kHz above the lower band edge 低频带边缘以上1 kHz
4. 3 kHz above the lower band edge 低频带边缘以上3 kHz

E1A03. What is the highest legal carrier frequency on the 20-meter band for transmitting a 2.8 kHz wide USB data signal? 传输2.8千赫宽USB数据信号时，20米波段的最高法定载波频率是多少？

1. 14.0708 MHz 14.0708兆赫
2. 14.1002 MHz 14.1002兆赫
3. 14.1472 MHz 14.1472兆赫
4. 14.3490 MHz 14.3490兆赫

E1A04. May an Extra class operator answer the CQ of a station on 3.601 MHz LSB phone? 特级接线员可以在3.601 MHz LSB电话上回答电台的CQ吗？

1. Yes, the entire signal will be inside the SSB allocation for Extra class operators 是的，整个信号将在特级操作员的SSB分配范围内
2. Yes, the displayed frequency is within the 75-meter phone band segment 是的，显示的频率在75米的电话频带段内
3. No, the sideband components will extend beyond the edge of the phone band segment 不，边带组件将延伸到电话频带段的边缘之外
4. No, US stations are not permitted to use phone emissions below 3.610 MHz 不，美国电台不允许使用低于3.610 MHz的电话发射

E1A05. Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States? 在美国有文件记录或注册的任何船只或工艺上，谁必须实际控制业余电台的电台设备？

1. Only a person with an FCC Marine Radio license grant 仅限获得FCC海洋无线电许可证的人员
2. Only a person named in an amateur station license grant 只有一个在业余电台执照授予中被点名的人
3. Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation 任何持有美国联邦通信委员会颁发的业余执照或被授权从事外国互惠业务的人
4. Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit 任何在业余电台执照授予中被点名的人或持有不受限制的无线电话操作员许可证的人

E1A06. What is the required transmit frequency of a CW signal for channelized 60 meter operation? 信道化60米操作所需的CW信号发射频率是多少？

1. At the lowest frequency of the channel 在频道的最低频率
2. At the center frequency of the channel 在通道的中心频率
3. At the highest frequency of the channel 在频道的最高频率
4. On any frequency where the signal’s sidebands are within the channel 在信号的边带位于信道内的任何频率上

E1A07. What is the maximum power permitted on the 2200-meter band? 2200米波段允许的最大功率是多少？

1. 50 watts PEP (peak envelope power) 50瓦PEP（峰值包络功率）
2. 100 watts PEP (peak envelope power) 100瓦PEP（峰值包络功率）
3. 1 watt EIRP (equivalent isotropic radiated power) 1瓦EIRP（等效各向同性辐射功率）
4. 5 watts EIRP (equivalent isotropic radiated power) 5瓦EIRP（等效各向同性辐射功率）

E1A08. If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation? 如果消息转发系统中的站点无意中转发了违反FCC规则的消息，谁将对违反规则负责？

1. The control operator of the packet bulletin board station 数据包公告板站的控制操作员
2. The control operator of the originating station 始发站的控制操作员
3. The control operators of all the stations in the system 系统中所有站点的控制操作员
4. The control operators of all the stations in the system not authenticating the source from which they accept communications 系统中所有站点的控制操作员未验证其接受通信的来源

E1A09. Except in some parts of Alaska, what is the maximum power permitted on the 630-meter band? 除了阿拉斯加的一些地区，630米波段允许的最大功率是多少？

1. 50 watts PEP (peak envelope power) 50瓦PEP（峰值包络功率）
2. 100 watts PEP (peak envelope power) 100瓦PEP（峰值包络功率）
3. 1 watt EIRP (equivalent isotropic radiated power) 1瓦EIRP（等效各向同性辐射功率）
4. 5 watts EIRP (equivalent isotropic radiated power) 5瓦EIRP（等效各向同性辐射功率）

E1A10. If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated? 如果业余电台安装在船上或飞机上，在电台运行之前必须满足什么条件？

1. Its operation must be approved by the master of the ship or the pilot in command of the aircraft 其操作必须得到船长或飞机驾驶员的批准
2. The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use 业余电台操作员必须同意在使用船舶或飞机的主无线电时不进行发射
3. The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply 业余站必须有一个完全独立于主船或飞机电源的电源
4. The amateur station must operate only in specific segments of the amateur service HF and VHF bands 业余电台必须仅在业余服务HF和VHF频带的特定区段中运行

E1A11. What licensing is required when operating an amateur station aboard a US-registered vessel in international waters? 在国际水域操作美国注册船只上的业余电台需要什么许可证？

1. Any amateur license with an FCC Marine or Aircraft endorsement 任何获得FCC海军或飞机认可的业余执照
2. Any FCC-issued amateur license 任何FCC颁发的业余许可证
3. Only General class or higher amateur licenses 只有普通级或更高级别的业余执照
4. An unrestricted Radiotelephone Operator Permit 不受限制的无线电话操作员许可证

E1B01. Which of the following constitutes a spurious emission? 以下哪项构成杂散发射？

1. An amateur station transmission made without the proper call sign identification 在没有正确呼号识别的情况下进行的业余电台传输
2. A signal transmitted to prevent its detection by any station other than the intended recipient 一种为防止被预期接收者以外的任何电台检测到而发送的信号
3. Any transmitted signal that unintentionally interferes with another licensed radio station and whose levels exceed 40 dB below the fundamental power level 任何无意干扰另一个许可无线电台的发射信号，其电平低于基本功率电平40 dB以上
4. An emission outside the signal’s necessary bandwidth that can be reduced or eliminated without affecting the information transmitted 在信号的必要带宽之外的发射，可以在不影响传输信息的情况下减少或消除

E1B02. Which of the following is an acceptable bandwidth for digital voice or slow-scan TV transmissions made on the HF amateur bands? 以下哪一项是在HF业余频带上进行数字语音或慢扫描电视传输的可接受带宽？

1. 3 kHz 3千赫
2. 10 kHz 10千赫
3. 15 kHz 15千赫
4. 20 kHz 20千赫

E1B03. Within what distance must an amateur station protect an FCC monitoring facility from harmful interference? 业余电台必须在多大距离内保护FCC监测设施免受有害干扰？

1. 1 mile 1英里
2. 3 miles 3英里
3. 10 miles 10英里
4. 30 miles 30英里

E1B04. What must the control operator of a repeater operating in the 70-centimeter band do if a radiolocation system experiences interference from that repeater? 如果无线电定位系统受到中继器的干扰，在70厘米波段工作的中继器的控制操作员必须做什么？

1. Reduce the repeater antenna HAAT (Height Above Average Terrain) 减小中继器天线HAAT（高度高于平均地形）
2. File an FAA NOTAM (Notice to Air Missions) with the repeater system's ERP, call sign, and six-character grid locator 将FAA NOTAM（空中任务通知）与中继器系统的ERP、呼号和六字符网格定位器一起存档
3. Cease operation or make changes to the repeater that mitigate the interference 停止操作或更改中继器以减轻干扰
4. All these choices are correct 所有这些选择都是正确的

E1B05. What is the National Radio Quiet Zone? 什么是国家无线电静默区？

1. An area surrounding the FCC monitoring station in Laurel, Maryland 马里兰州劳雷尔市联邦通信委员会监测站周围的区域
2. An area in New Mexico surrounding the White Sands Test Area 新墨西哥州白沙试验区周围的一个区域
3. An area surrounding the National Radio Astronomy Observatory 国家射电天文台周围的区域
4. An area in Florida surrounding Cape Canaveral 佛罗里达州卡纳维拉尔角周围的一个地区

E1B06. Which of the following additional rules apply if you are erecting an amateur station antenna structure at a site at or near a public use airport? 如果您在公共机场或附近的场地安装业余电台天线结构，以下哪些附加规则适用？

1. You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules 您可能需要通知美国联邦航空管理局，并按照FCC规则第17部分的要求在FCC注册
2. You may have to enter the height above ground in meters, and the latitude and longitude in degrees, minutes, and seconds on the FAA website 您可能需要在FAA网站上输入地面以上的高度（以米为单位），以及纬度和经度（以度、分和秒为单位）
3. You must file an Environmental Impact Statement with the EPA before construction begins 施工开始前，您必须向环保局提交环境影响声明
4. You must obtain a construction permit from the airport zoning authority per Part 119 of the FAA regulations 根据FAA条例第119部分，您必须从机场分区管理局获得施工许可

E1B07. To what type of regulations does PRB-1 apply? PRB-1适用于哪种类型的法规？

1. Homeowners associations 房主协会
2. FAA tower height limits FAA塔架高度限制
3. State and local zoning 州和地方分区
4. Use of wireless devices in vehicles 无线设备在车辆中的使用

E1B08. What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design? 假设所涉及的接收器具有良好的工程设计，如果业余电台的信号对国内广播接收造成干扰，联邦通信委员会会对其进行哪些限制？

1. The amateur station must cease operation 业余电台必须停止运营
2. The amateur station must cease operation on all frequencies below 30 MHz 业余电台必须停止在低于30 MHz的所有频率上运行
3. The amateur station must cease operation on all frequencies above 30 MHz 业余电台必须停止在30 MHz以上的所有频率上运行
4. The amateur station must avoid transmitting during certain hours on frequencies that cause the interference 业余电台必须避免在特定时间内以造成干扰的频率进行发射

E1B09. Which amateur stations may be operated under RACES rules? 哪些业余电台可以根据比赛规则运营？

1. Only those club stations licensed to Amateur Extra class operators 只有那些授权给业余特级运营商的俱乐部电台
2. Any FCC-licensed amateur station except a Technician class 任何FCC许可的业余电台，技术员除外
3. Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served 任何经服务地区负责民防组织认证的FCC许可业余电台
4. Only stations meeting the FCC Part 97 technical standards for operation during an emergency 只有符合FCC第97部分紧急情况下运行技术标准的电台

E1B10. What frequencies are authorized to an amateur station operating under RACES rules? 根据RACES规则，业余电台可以使用哪些频率？

1. All amateur service frequencies authorized to the control operator 授权给控制操作员的所有业余服务频率
2. Specific segments in the amateur service MF, HF, VHF, and UHF bands 业余服务MF、HF、VHF和UHF频带中的特定段
3. Specific local government channels 具体的地方政府渠道
4. All these choices are correct 所有这些选择都是正确的

E1B11. What does PRB-1 require of state and local regulations affecting amateur radio antenna size and structures? PRB-1对影响业余无线电天线尺寸和结构的州和地方法规有什么要求？

1. No limitations may be placed on antenna size or placement 天线尺寸或位置不受限制
2. Reasonable accommodations of amateur radio must be made 必须为业余无线电提供合理的住宿
3. Such structures must be permitted when use for emergency communications can be demonstrated 当可以证明用于紧急通信时，必须允许使用此类结构
4. Such structures must be permitted if certified by a registered professional engineer 此类结构必须经注册专业工程师认证后方可使用

E1C01. What is the maximum bandwidth for a data emission on 60 meters? 60米数据发射的最大带宽是多少？

1. 60 Hz 60赫兹
2. 170 Hz 170赫兹
3. 1.5 kHz 1.5千赫
4. 2.8 kHz 2.8千赫

E1C02. Which of the following apply to communications transmitted to amateur stations in foreign countries? 以下哪项适用于发送到外国业余电台的通信？

1. Third party traffic must be limited to that intended for the exclusive use of government and non-Government Organization (NGOs) involved in emergency relief activities 第三方交通必须仅限于参与紧急救援活动的政府和非政府组织的专用交通
2. All transmissions must be in English 所有变速器必须为英语
3. Communications must be limited to those incidental to the purpose of the amateur service and remarks of a personal nature 通信必须仅限于业余服务目的附带的内容和个人性质的言论
4. All these choices are correct 所有这些选择都是正确的

E1C03. How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200-meter or 630-meter band? 运营商在向公用事业技术委员会（UTC）提交通知后，必须等待多长时间才能在2200米或630米波段上运营？

1. Operators must not operate until approval is received 在获得批准之前，操作员不得操作
2. Operators may operate after 30 days, providing they have not been told that their station is within 1 kilometer of PLC systems using those frequencies 运营商可以在30天后运营，前提是他们没有被告知他们的站点在使用这些频率的PLC系统的1公里范围内
3. Operators may not operate until a test signal has been transmitted in coordination with the local power company 在与当地电力公司协调传输测试信号之前，操作员不得操作
4. Operations may commence immediately, and may continue unless interference is reported by the UTC 操作可以立即开始，并且可以继续，除非UTC报告干扰

E1C04. What is an IARP? 什么是IARP？

1. A permit that allows US amateurs to operate in certain countries of the Americas 允许美国业余爱好者在美洲某些国家活动的许可证
2. The internal amateur radio practices policy of the FCC FCC的内部业余无线电实践政策
3. An indication of increased antenna reflected power 天线反射功率增加的指示
4. A forecast of intermittent aurora radio propagation 间歇性极光无线电传播的预测

E1C05. Under what situation may a station transmit third party communications while being automatically controlled? 在什么情况下，电台可以在自动控制的情况下传输第三方通信？

1. Never 从不
2. Only when transmitting RTTY or data emissions 仅当传输RTTY或数据发射时
3. Only when transmitting SSB or CW 仅当发送SSB或CW时
4. On any mode approved by the National Telecommunication and Information Administration 关于国家电信和信息管理局批准的任何模式

E1C06. Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted? 在允许的情况下，在外国按照CEPT规则运营需要以下哪一项？

1. You must identify in the official language of the country in which you are operating 您必须用经营所在国家的官方语言进行识别
2. The US embassy must approve of your operation 美国大使馆必须批准你的行动
3. You must have a copy of FCC Public Notice DA 16-1048 您必须有FCC公告DA 16-1048的副本
4. You must append "/CEPT" to your call sign 您必须在呼号后面加上“/CEPT”

E1C07. What notifications must be given before transmitting on the 630- or 2200-meter bands? 在630米或2200米波段上传输之前，必须发出哪些通知？

1. A special endorsement must be requested from the FCC 必须向FCC申请特殊背书
2. An environmental impact statement must be filed with the Department of the Interior 必须向内政部提交环境影响声明
3. Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway 运营商必须告知FAA他们的运营意图，并给出他们的呼号和到最近跑道的距离
4. Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station 操作员必须将其呼号和车站坐标通知公用事业技术委员会（UTC）

E1C08. What is the maximum permissible duration of a remotely controlled station’s transmissions if its control link malfunctions? 如果远程控制站的控制链路发生故障，其传输的最大允许持续时间是多少？

1. 30 seconds 30秒
2. 3 minutes 3分钟
3. 5 minutes 5分钟
4. 10 minutes 10分钟

E1C09. What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz? 对于低于29.0 MHz的角度调制，在最高调制频率下允许的最高调制指数是多少？

1. 0.5 0.5
2. 1 1
3. 2 2
4. 3 3

E1C10. What is the maximum mean power level for a spurious emission below 30 MHz with respect to the fundamental emission? 相对于基本发射，低于30 MHz的杂散发射的最大平均功率电平是多少？

1. - 43 dB -43分贝
2. - 53 dB -53分贝
3. - 63 dB -63分贝
4. - 73 dB -73分贝

E1C11. Which of the following operating arrangements allows an FCC-licensed US citizen to operate in many European countries, and amateurs from many European countries to operate in the US? 以下哪项操作安排允许获得FCC许可的美国公民在许多欧洲国家进行操作，以及允许来自许多欧洲国家的业余爱好者在美国进行操作？

1. CEPT 接受
2. IARP
3. ITU reciprocal license ITU互惠许可证
4. All these choices are correct 所有这些选择都是正确的

E1C12. In what portion of the 630-meter band are phone emissions permitted? 在630米波段的哪一部分允许手机发射？

1. None 没有一个
2. Only the top 3 kHz 仅顶部3 kHz
3. Only the bottom 3 kHz 仅底部3 kHz
4. The entire band 整个波段

E1D01. What is the definition of telemetry? 遥测的定义是什么？

1. One-way transmission of measurements at a distance from the measuring instrument 距离测量仪器一定距离处的单向测量传输
2. Two-way transmissions in excess of 1000 feet 超过1000英尺的双向变速器
3. Two-way transmissions of data 双向数据传输
4. One-way transmission that initiates, modifies, or terminates the functions of a device at a distance 启动、修改或终止远处设备功能的单向传输

E1D02. Which of the following may transmit encrypted messages? 以下哪项可以传输加密消息？

1. Telecommand signals to terrestrial repeaters 至地面中继器的遥控信号
2. Telecommand signals from a space telecommand station 来自太空遥控站的遥控信号
3. Auxiliary relay links carrying repeater audio 承载中继器音频的辅助中继链路
4. Mesh network backbone nodes 网状网络骨干节点

E1D03. What is a space telecommand station? 什么是太空远程通信站？

1. An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites 位于地球表面的业余台站，通过地球卫星与其他地球台站进行通信
2. An amateur station that transmits communications to initiate, modify, or terminate functions of a space station 一种业余空间站，用于发送通信以启动、修改或终止空间站的功能
3. An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth 位于地球表面上方50多公里的卫星或气球上的业余空间站
4. An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth 接收来自地球表面50多公里以上卫星或气球的遥测数据的业余站

E1D04. Which of the following is required in the identification transmissions from a balloon-borne telemetry station? 气球载遥测站的识别传输需要以下哪一项？

1. Call sign 呼号
2. The output power of the balloon transmitter 气球发射器的输出功率
3. The station's six-character Maidenhead grid locator 车站的六个字符的梅登黑德网格定位器
4. All these choices are correct 所有这些选择都是正确的

E1D05. What must be posted at the location of a station being operated by telecommand on or within 50 kilometers of the Earth’s surface? 在地球表面上或距离地球表面50公里以内的远程通信站的位置上必须张贴什么？

1. A photocopy of the station license 车站执照复印件
2. A label with the name, address, and telephone number of the station licensee 带有车站持牌人姓名、地址和电话号码的标签
3. A label with the name, address, and telephone number of the control operator 带有控制操作员姓名、地址和电话号码的标签
4. All these choices are correct 所有这些选择都是正确的

E1D06. What is the maximum permitted transmitter output power when operating a model craft by telecommand? 遥控操作模型飞行器时，允许的最大发射机输出功率是多少？

1. 1 watt 1瓦
2. 2 watts 2瓦
3. 5 watts 5瓦
4. 100 watts 100瓦

E1D07. Which group of HF amateur bands include allocations for space stations? 哪一组HF业余波段包括空间站的分配？

1. 40 meters, 20 meters, 15 meters, and 10 meters 40米、20米、15米和10米
2. 30 meters, 17 meters, and 10 meters 30米、17米和10米
3. Only 10 meters 只有10米
4. Satellite operation is permitted on all HF bands 允许在所有高频频带上进行卫星操作

E1D08. Which VHF amateur bands have frequencies authorized for space stations? 哪些甚高频业余波段的频率被授权用于空间站？

1. 6 meters and 2 meters 6米和2米
2. 6 meters, 2 meters, and 1.25 meters 6米、2米和1.25米
3. 2 meters and 1.25 meters 2米和1.25米
4. 2 meters 2米

E1D09. Which UHF amateur bands have frequencies authorized for space stations? 哪些超高频业余频段的频率被授权用于空间站？

1. 70 centimeters only 仅70厘米
2. 70 centimeters and 13 centimeters 70厘米和13厘米
3. 70 centimeters and 33 centimeters 70厘米和33厘米
4. 33 centimeters and 13 centimeters 33厘米和13厘米

E1D10. Which amateur stations are eligible to be telecommand stations of space stations, subject to the privileges of the class of operator license held by the control operator of the station? 哪些业余空间站有资格成为空间站的远程通信站，并享有空间站控制操作员持有的操作员执照类别的特权？

1. Any amateur station approved by AMSAT AMSAT批准的任何业余电台
2. Any amateur station so designated by the space station licensee 空间站持牌人如此指定的任何业余空间站
3. Any amateur station so designated by the ITU 国际电联如此指定的任何业余电台
4. All these choices are correct 所有这些选择都是正确的

E1D11. Which amateur stations are eligible to operate as Earth stations? 哪些业余台站有资格作为地球台站运行？

1. Any amateur licensee who has successfully completed the AMSAT space communications course 任何成功完成AMSAT空间通信课程的业余持牌人
2. Only those of General, Advanced or Amateur Extra class operators 仅适用于普通、高级或业余特级操作员
3. Only those of Amateur Extra class operators 只有那些业余特级操作员
4. Any amateur station, subject to the privileges of the class of operator license held by the control operator 任何业余站，受控制操作员持有的操作员执照类别的特权约束

E1D12. Which of the following amateur stations may transmit one-way communications? 以下哪一个业余电台可以传输单向通信？

1. A space station, beacon station, or telecommand station 空间站、信标站或远程通信站
2. A local repeater or linked repeater station 本地中继站或链接中继站
3. A message forwarding station or automatically controlled digital station 消息转发站或自动控制的数字站
4. All these choices are correct 所有这些选择都是正确的

E1E01. For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed? 第97部分规则规定VEs和VEC可以报销哪些类型的自付费用？

1. Preparing, processing, administering, and coordinating an examination for an amateur radio operator license 业余无线电操作员执照考试的准备、处理、管理和协调
2. Teaching an amateur operator license examination preparation course 教授业余操作员执照考试准备课程
3. No expenses are authorized for reimbursement 不允许报销任何费用
4. Providing amateur operator license examination preparation training materials 提供业余操作员执照考试准备培训材料

E1E02. Who is tasked by Part 97 with maintaining the pools of questions for all US amateur license examinations? 第97部分的任务是谁维护所有美国业余执照考试的问题库？

1. The VEs VEs
2. The FCC FCC
3. The VECs VEC
4. The ARRL ARRL

E1E03. What is a Volunteer Examiner Coordinator? 什么是志愿考官协调员？

1. A person who has volunteered to administer amateur operator license examinations 自愿参加业余操作员执照考试的人
2. An organization paid by the volunteer examiner team to publicize and schedule examinations 由志愿考官团队付费的一个组织，用于宣传和安排考试
3. An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations 与联邦通信委员会签订协议，协调、准备和管理业余运营商执照考试的组织
4. The person who has entered into an agreement with the FCC to be the VE session manager 已与FCC签订协议的人员将担任VE会话管理员

E1E04. What is required to be accredited as a Volunteer Examiner? 被认定为志愿考官需要什么？

1. Each General, Advanced and Amateur Extra class operator is automatically accredited as a VE when the license is granted 授予许可证后，每个普通、高级和业余特级操作员都会自动获得VE认证
2. The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau 申请的业余运营商必须通过FCC执法局管理的VE考试
3. The prospective VE must obtain accreditation from the FCC 潜在的VE必须获得FCC的认证
4. A VEC must confirm that the VE applicant meets FCC requirements to serve as an examiner VEC必须确认VE申请人符合FCC的要求才能担任审查员

E1E05. What must the VE team do with the application form if the examinee does not pass the exam? 如果考生没有通过考试，VE团队必须如何处理申请表？

1. Maintain the application form with the VEC’s records 保存申请表和VEC的记录
2. Return the application document to the examinee 将申请文件退还给考生
3. Send the application form to the FCC and inform the FCC of the grade 将申请表发送给FCC，并告知FCC等级
4. Destroy the application form 销毁申请表

E1E06. Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session? 谁负责业余操作员执照考试期间的适当行为和必要监督？

1. The VEC coordinating the session VEC协调会议
2. The designated monitoring VE 指定的监控VE
3. Each administering VE 每次服用VE
4. Only the VE session manager 只有VE会话管理员

E1E07. What should a VE do if a candidate fails to comply with the examiner’s instructions during an amateur operator license examination? 如果考生在业余操作员执照考试中没有遵守考官的指示，VE应该怎么办？

1. Warn the candidate that continued failure to comply will result in termination of the examination 警告考生继续不遵守规定将导致考试终止
2. Immediately terminate the candidate’s examination 立即终止考生的考试
3. Allow the candidate to complete the examination, but invalidate the results 允许考生完成考试，但成绩无效
4. Immediately terminate everyone’s examination and close the session 立即终止所有人的检查并结束会话

E1E08. To which of the following examinees may a VE not administer an examination? VE可以不对以下哪一位考生进行考试？

1. Employees of the VE VE的员工
2. Friends of the VE VE之友
3. Relatives of the VE as listed in the FCC rules FCC规则中列出的VE的亲属
4. All these choices are correct 所有这些选择都是正确的

E1E09. What may be the penalty for a VE who fraudulently administers or certifies an examination? 对于欺诈性地管理或认证考试的VE，可能会受到什么处罚？

1. Revocation of the VE’s amateur station license grant and the suspension of the VE’s amateur operator license grant 撤销VE的业余电台许可证授予和暂停VE的业余运营商许可证授予
2. A fine of up to $1,000 per occurrence 每次最高罚款1000美元
3. A sentence of up to one year in prison 最高可判处一年监禁
4. All these choices are correct 所有这些选择都是正确的

E1E10. What must the administering VEs do after the administration of a successful examination for an amateur operator license? 在业余操作员执照考试成功后，管理VEs必须做什么？

1. They must collect and send the documents directly to the FCC 他们必须收集文件并直接发送给FCC
2. They must collect and submit the documents to the coordinating VEC for grading 他们必须收集文件并提交给协调VEC进行评分
3. They must submit the application document to the coordinating VEC according to the coordinating VEC instructions 他们必须根据协调VEC的指示向协调VEC提交申请文件
4. They must return the documents to the applicant for submission to the FCC according to the FCC instructions 他们必须将文件退还给申请人，以便根据FCC的指示提交给FCC

E1E11. What must the VE team do if an examinee scores a passing grade on all examination elements needed for an upgrade or new license? 如果考生在升级或新执照所需的所有考试要素上都取得了及格分数，VE团队该怎么办？

1. Photocopy all examination documents and forward them to the FCC for processing 复印所有考试文件并将其转发给FCC进行处理
2. Three VEs must certify that the examinee is qualified for the license grant and that they have complied with the administering VE requirements 三个VE必须证明考生有资格获得执照授予，并且他们遵守了管理VE的要求
3. Issue the examinee the new or upgrade license 为考生颁发新的或升级的驾照
4. All these choices are correct 所有这些选择都是正确的

E1F01. On what frequencies are spread spectrum transmissions permitted? 在什么频率上允许扩频传输？

1. Only on amateur frequencies above 50 MHz 仅适用于50 MHz以上的业余频率
2. Only on amateur frequencies above 222 MHz 仅适用于222 MHz以上的业余频率
3. Only on amateur frequencies above 420 MHz 仅适用于420 MHz以上的业余频率
4. Only on amateur frequencies above 144 MHz 仅适用于144 MHz以上的业余频率

E1F02. What privileges are authorized in the US to persons holding an amateur service license granted by the government of Canada? 在美国，持有加拿大政府颁发的业余服务许可证的人有哪些特权？

1. None, they must obtain a US license 没有，他们必须获得美国许可证
2. Full privileges of the General class license on the 80-, 40-, 20-, 15-, and 10-meter bands 80米、40米、20米、15米和10米波段普通级许可证的全部特权
3. The operating terms and conditions of the Canadian amateur service license, not to exceed US Amateur Extra class license privileges 加拿大业余服务许可证的操作条款和条件，不得超过美国业余特级许可证特权
4. Full privileges, up to and including those of the Amateur Extra class license, on the 80-, 40-, 20-, 15-, and 10-meter bands 在80米、40米、20米、15米和10米波段享有完全特权，最高可达并包括业余特级执照

E1F03. Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification? 如果未获得FCC认证，经销商在什么情况下可以销售能够在144 MHz以下工作的外部RF功率放大器？

1. Gain is less than 23 dB when driven by power of 10 watts or less 当功率小于或等于10瓦时，增益小于23 dB
2. The equipment dealer assembled it from a kit 设备经销商用套件组装
3. It was manufactured and certificated in a country which has a reciprocal certification agreement with the FCC 它是在一个与美国联邦通信委员会有互惠认证协议的国家制造和认证的
4. It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator’s station 它是在使用状态下从一名业余运营商处购买的，并出售给另一名业余运营者在该运营商的站点使用

E1F04. Which of the following geographic descriptions approximately describes "Line A"? 以下哪个地理描述大致描述了“线路A”？

1. A line roughly parallel to and south of the border between the US and Canada 大致平行于美国和加拿大边界以南的一条线
2. A line roughly parallel to and west of the US Atlantic coastline 大致平行于美国大西洋海岸线并位于其西面的一条线
3. A line roughly parallel to and north of the border between the US and Mexico 大致平行于美国和墨西哥边界以北的一条线
4. A line roughly parallel to and east of the US Pacific coastline 大致平行于美国太平洋海岸线并向东的一条线

E1F05. Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A? 如果业余电台位于相邻的48个州和A线以北，它们可能不会在以下哪一个频率段进行传输？

1. 440 MHz - 450 MHz 440兆赫-450兆赫
2. 53 MHz - 54 MHz 53兆赫-54兆赫
3. 222 MHz - 223 MHz 222兆赫-223兆赫
4. 420 MHz - 430 MHz 420兆赫-430兆赫

E1F06. Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station? 在什么情况下，联邦通信委员会可以向业余电台颁发特别临时管理局（STA）？

1. To provide for experimental amateur communications 提供实验性业余通信
2. To allow use of a special event call sign 允许使用特殊事件呼号
3. To allow a VE group with less than three VEs to administer examinations in a remote, sparsely populated area 允许一个VEs少于三个的VE小组在偏远、人烟稀少的地区进行检查
4. To allow a licensee who has passed an upgrade exam to operate with upgraded privileges while waiting for posting on the FCC database 允许通过升级考试的被许可人在等待发布到FCC数据库时使用升级后的权限进行操作

E1F07. When may an amateur station send a message to a business? 业余电台什么时候可以向企业发送消息？

1. When the pecuniary interest of the amateur or his or her employer is less than $25 当业余爱好者或其雇主的金钱利益低于25美元时
2. When the pecuniary interest of the amateur or his or her employer is less than $50 当业余爱好者或其雇主的金钱利益低于50美元时
3. At no time 任何时候都不会
4. When neither the amateur nor their employer has a pecuniary interest in the communications 当业余爱好者和他们的雇主在通信中都没有金钱利益时

E1F08. Which of the following types of amateur station communications are prohibited? 以下哪种类型的业余电台通信是被禁止的？

1. Communications transmitted for hire or material compensation, except as otherwise provided in the rules 为雇佣或物质补偿而传输的通信，除非规则另有规定
2. Communications that have political content, except as allowed by the Fairness Doctrine 具有政治内容的通信，除非公平原则允许
3. Communications that have religious content 具有宗教内容的通信
4. Communications in a language other than English 用英语以外的语言进行交流

E1F09. Which of the following cannot be transmitted over an amateur radio mesh network? 以下哪项不能通过业余无线电网状网络进行传输？

1. Third party traffic 第三方流量
2. Email 电子邮件
3. Messages encoded to obscure their meaning 被编码以模糊其含义的信息
4. All these choices are correct 所有这些选择都是正确的

E1F10. Who may be the control operator of an auxiliary station? 谁可能是辅助站的控制操作员？

1. Any licensed amateur operator 任何有执照的业余操作员
2. Only Technician, General, Advanced, or Amateur Extra class operators 仅限技术员、普通操作员、高级操作员或业余特级操作员
3. Only General, Advanced, or Amateur Extra class operators 仅限普通、高级或业余特级操作员
4. Only Amateur Extra class operators 仅限业余特级操作员

E1F11. Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification? 如果外部射频功率放大器有资格获得FCC认证，以下哪一项最能描述其必须满足的标准之一？

1. It must produce full legal output when driven by not more than 5 watts of mean RF input power 当由不超过5瓦的平均射频输入功率驱动时，它必须产生完全合法的输出
2. It must have received an Underwriters Laboratory certification for electrical safety as well as having met IEEE standard 14.101(B) 它必须已获得美国保险商实验室的电气安全认证，并符合IEEE标准14.101（B）
3. It must exhibit a gain of less than 23 dB when driven by 10 watts or less 当驱动功率小于或等于10瓦时，其增益必须小于23 dB
4. It must satisfy the FCC’s spurious emission standards when operated at the lesser of 1500 watts or its full output power 当以1500瓦或其全输出功率中的较小者运行时，它必须满足FCC的杂散发射标准

E2A01. What is the direction of an ascending pass for an amateur satellite? 业余卫星上升通道的方向是什么？

1. From west to east 从西向东
2. From east to west 从东向西
3. From south to north 从南到北
4. From north to south 从北向南

E2A02. Which of the following is characteristic of an inverting linear transponder? 以下哪项是反向线性转发器的特性？

1. Doppler shift is reduced because the uplink and downlink shifts are in opposite directions 多普勒频移减少，因为上行链路和下行链路的频移方向相反
2. Signal position in the band is reversed 频带中的信号位置颠倒
3. Upper sideband on the uplink becomes lower sideband on the downlink, and vice versa 上行链路上的上边带变为下行链路上的下边带，反之亦然
4. All these choices are correct 所有这些选择都是正确的

E2A03. How is an upload signal processed by an inverting linear transponder? 反向线性转发器是如何处理上传信号的？

1. The signal is detected and remodulated on the reverse sideband 在反向边带上检测并重新调制信号
2. The signal is passed through a nonlinear filter 信号通过非线性滤波器
3. The signal is reduced to I and Q components, and the Q component is filtered out 信号被减少为I和Q分量，Q分量被滤除
4. The signal is mixed with a local oscillator signal and the difference product is transmitted 该信号与本地振荡器信号混合，并传输差积

E2A04. What is meant by the “mode” of an amateur radio satellite? 业余无线电卫星的“模式”是什么意思？

1. Whether the satellite is in a low earth or geostationary orbit 无论卫星是在近地轨道还是地球静止轨道
2. The satellite’s uplink and downlink frequency bands 卫星的上行链路和下行链路频带
3. The satellite’s orientation with respect to the Earth 卫星相对于地球的方位
4. Whether the satellite is in a polar or equatorial orbit 卫星是在极地轨道还是在赤道轨道

E2A05. What do the letters in a satellite’s mode designator specify? 卫星模式指示符中的字母指定了什么？

1. Power limits for uplink and downlink transmissions 上行链路和下行链路传输的功率限制
2. The location of the ground control station 地面控制站的位置
3. The polarization of uplink and downlink signals 上行链路和下行链路信号的极化
4. The uplink and downlink frequency ranges 上行和下行频率范围

E2A06. What are Keplerian elements? 开普勒元素是什么？

1. Parameters that define the orbit of a satellite 定义卫星轨道的参数
2. Phase reversing elements in a Yagi antenna 八木天线中的相位反转元件
3. High-emission heater filaments used in magnetron tubes 用于磁控管的高发射加热器灯丝
4. Encrypting codes used for spread spectrum modulation 用于扩频调制的加密码

E2A07. Which of the following types of signals can be relayed through a linear transponder? 以下哪种类型的信号可以通过线性转发器进行中继？

1. FM and CW FM和CW
2. SSB and SSTV SSB和SSTV
3. PSK and packet PSK和数据包
4. All these choices are correct 所有这些选择都是正确的

E2A08. Why should effective radiated power (ERP) be limited to a satellite that uses a linear transponder? 为什么有效辐射功率（ERP）应限于使用线性转发器的卫星？

1. To prevent creating errors in the satellite telemetry 防止在卫星遥测中产生错误
2. To avoid reducing the downlink power to all other users 为避免降低所有其他用户的下行链路功率
3. To prevent the satellite from emitting out-of-band signals 防止卫星发射带外信号
4. To avoid interfering with terrestrial QSOs 避免干扰地面QSO

E2A09. What do the terms “L band” and “S band” specify? 术语“L波段”和“S波段”规定了什么？

1. The 23- and 13-centimeter bands 23厘米和13厘米波段
2. The 2-meter and 70-centimeter bands 2米和70厘米的带子
3. FM and digital store-and-forward systems 调频和数字存储转发系统
4. Which sideband to use 使用哪个边带

E2A10. What type of satellite appears to stay in one position in the sky? 什么类型的卫星似乎停留在天空中的一个位置？

1. HEO 呵呵
2. Geostationary 地球静止
3. Geomagnetic 地磁
4. LEO 狮子座

E2A11. What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation? 什么类型的天线可以用来最小化自旋调制和法拉第旋转的影响？

1. A linearly polarized antenna 线性极化天线
2. A circularly polarized antenna 圆极化天线
3. An isotropic antenna 各向同性天线
4. A log-periodic dipole array 对数周期偶极子阵列

E2A12. What is the purpose of digital store-and-forward functions on an amateur radio satellite? 业余无线电卫星上的数字存储和转发功能的目的是什么？

1. To upload operational software for the transponder 上传应答器的操作软件
2. To delay download of telemetry between satellites 延迟卫星间遥测数据的下载
3. To hold digital messages in the satellite for later download 将数字消息保存在卫星中以供以后下载
4. To relay messages between satellites 在卫星之间中继消息

E2A13. Which of the following techniques is used by digital satellites to relay messages? 数字卫星使用以下哪种技术来中继消息？

1. Digipeating 数字化
2. Store-and-forward 存储并转发
3. Multisatellite relaying 多卫星中继
4. Node hopping 节点跳变

E2B01. In digital television, what does a coding rate of 3/4 mean? 在数字电视中，3/4的编码率意味着什么？

1. 25% of the data sent is forward error correction data 发送的数据中有25%是前向纠错数据
2. Data compression reduces data rate by 3/4 数据压缩将数据速率降低3/4
3. 1/4 of the time interval is used as a guard interval 时间间隔的1/4用作保护间隔
4. Three, four-bit words are used to transmit each pixel 三、四位字用于传输每个像素

E2B02. How many horizontal lines make up a fast-scan (NTSC) television frame? 一个快速扫描（NTSC）电视帧由多少条水平线组成？

1. 30 30
2. 60 60
3. 525 525
4. 1080 1080

E2B03. How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system? 如何在快速扫描（NTSC）电视系统中生成隔行扫描模式？

1. By scanning two fields simultaneously 通过同时扫描两个场
2. By scanning each field from bottom-to-top 通过从下到上扫描每个字段
3. By scanning lines from left-to-right in one field and right-to-left in the next 通过在一个场中从左到右扫描行，在下一场中从右到左扫描行
4. By scanning odd-numbered lines in one field and even-numbered lines in the next 通过扫描一个场中的奇数行和下一场中的偶数行

E2B04. How is color information sent in analog SSTV? 如何在模拟SSTV中发送颜色信息？

1. Color lines are sent sequentially 按顺序发送彩色行
2. Color information is sent on a 2.8 kHz subcarrier 颜色信息在2.8 kHz的子载波上发送
3. Color is sent in a color burst at the end of each line 颜色以彩色连拍的形式发送到每行的末尾
4. Color is amplitude modulated on the frequency modulated intensity signal 颜色在调频强度信号上进行幅度调制

E2B05. Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions? 以下哪项描述了残余边带在模拟快速扫描电视传输中的使用？

1. The vestigial sideband carries the audio information 残留边带携带音频信息
2. The vestigial sideband contains chroma information 残留边带包含色度信息
3. Vestigial sideband reduces the bandwidth while increasing the fidelity of low frequency video components 残留边带降低了带宽，同时提高了低频视频分量的保真度
4. Vestigial sideband provides high frequency emphasis to sharpen the picture 残留边带提供高频强调以锐化图像

E2B06. What is vestigial sideband modulation? 什么是残留边带调制？

1. Amplitude modulation in which one complete sideband and a portion of the other are transmitted 振幅调制，其中一个完整的边带和另一个边带的一部分被传输
2. A type of modulation in which one sideband is inverted 一种边带反转的调制方式
3. Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier 在对载波进行频率调制之前，通过对音频中的一个边带进行滤波来实现窄带FM调制
4. Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation 通过在单边带幅度调制之后应用FM调制实现扩频调制

E2B07. Which types of modulation are used for amateur television DVB-T signals? 业余电视DVB-T信号使用哪些类型的调制？

1. FM and FSK FM和FSK
2. QAM and QPSK QAM和QPSK
3. AM and OOK 上午和下午
4. All these choices are correct 所有这些选择都是正确的

E2B08. What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70-centimeter band? 什么技术允许商业模拟电视接收机用于70厘米波段的快速扫描电视操作？

1. Transmitting on channels shared with cable TV 在与有线电视共享的频道上传输
2. Using converted satellite TV dishes 使用转换后的卫星电视碟形天线
3. Transmitting on the abandoned TV channel 2 在废弃的电视频道2上传输
4. Using USB and demodulating the signal with a computer sound card 使用USB和计算机声卡对信号进行解调

E2B09. What kind of receiver can be used to receive and decode SSTV using the Digital Radio Mondiale (DRM) protocol? 使用数字世界广播（DRM）协议，可以使用哪种接收器来接收和解码SSTV？

1. CDMA 码分多址
2. AREDN 阿伦
3. AM 调幅
4. SSB

E2B10. What aspect of an analog slow-scan television signal encodes the brightness of the picture? 模拟慢扫描电视信号的哪个方面对画面的亮度进行编码？

1. Tone frequency 音调频率
2. Tone amplitude 音调幅度
3. Sync amplitude 同步幅度
4. Sync frequency 同步频率

E2B11. What is the function of the vertical interval signaling (VIS) code sent as part of an SSTV transmission? 作为SSTV传输的一部分发送的垂直间隔信号（VIS）代码的功能是什么？

1. To lock the color burst oscillator in color SSTV images 在彩色SSTV图像中锁定彩色连拍振荡器
2. To identify the SSTV mode being used 识别正在使用的SSTV模式
3. To provide vertical synchronization 提供垂直同步
4. To identify the call sign of the station transmitting 识别发送电台的呼号

E2B12. What signals SSTV receiving software to begin a new picture line? 什么信号SSTV接收软件开始新的图像线？

1. Specific tone frequencies 特定音调频率
2. Elapsed time 运行时间
3. Specific tone amplitudes 特定音调振幅
4. A two-tone signal 双音信号

E2C01. What indicator is required to be used by US-licensed operators when operating a station via remote control and the remote transmitter is located in the US? 当通过远程控制操作电台并且远程发射器位于美国时，美国许可的操作员需要使用什么指示器？

1. / followed by the USPS two-letter abbreviation for the state in which the remote station is located /后面是USPS两个字母的缩写，表示远程站所在的州
2. /R# where # is the district of the remote station /R#，其中#是远程站点的区域
3. / followed by the ARRL Section of the remote station /然后是远程站的ARRL部分
4. No additional indicator is required 不需要额外的指示器

E2C02. Which of the following file formats is used for exchanging amateur radio log data? 以下哪种文件格式用于交换业余无线电日志数据？

1. NEC 日本电气股份有限公司
2. ARLD
3. ADIF
4. OCF

E2C03. From which of the following bands is amateur radio contesting generally excluded? 业余无线电比赛通常被排除在以下哪个波段之外？

1. 30 meters 30米
2. 6 meters 6米
3. 70 centimeters 70厘米
4. 33 centimeters 33厘米

E2C04. Which of the following frequencies can be used for amateur radio mesh networks? 以下哪个频率可用于业余无线电网状网络？

1. HF frequencies where digital communications are permitted 允许数字通信的HF频率
2. Frequencies shared with various unlicensed wireless data services 与各种未经许可的无线数据服务共享的频率
3. Cable TV channels 41-43 有线电视频道41-43
4. The 60-meter band channel centered on 5373 kHz 以5373 kHz为中心的60米波段信道

E2C05. What is the function of a DX QSL Manager? DX QSL 管理员的职能是什么？

1. Allocate frequencies for DXpeditions 为DXpedics分配频率
2. Handle the receiving and sending of confirmations for a DX station 处理DX工作站的确认接收和发送
3. Run a net to allow many stations to contact a rare DX station 运行一个网络，允许许多电台联系一个罕见的DX电台
4. Communicate to a DXpedition about propagation, band openings, pileup conditions, etc. 与DXpedion沟通传播、频带开口、堆积条件等。

E2C06. During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity? 在甚高频/超高频比赛中，你希望在哪个波段找到最高水平的单边带或连续波活动？

1. At the top of each band, usually in a segment reserved for contests 在每个波段的顶部，通常在为比赛保留的片段中
2. In the middle of each band, usually on the national calling frequency 在每个频段的中间，通常在国家呼叫频率上
3. In the weak signal segment of the band, with most of the activity near the calling frequency 在频带的弱信号段，大部分活动接近主叫频率
4. In the middle of the band, usually 25 kHz above the national calling frequency 在频带中间，通常高于国家呼叫频率25 kHz

E2C07. What is the Cabrillo format? 什么是Cabrillo格式？

1. A standard for submission of electronic contest logs 电子竞赛日志提交标准
2. A method of exchanging information during a contest QSO 一种在比赛中交换信息的方法QSO
3. The most common set of contest rules 最常见的一套竞赛规则
4. A digital protocol specifically designed for rapid contest exchanges 专为快速比赛交换而设计的数字协议

E2C08. Which of the following contacts may be confirmed through the Logbook of The World (LoTW)? 以下哪些联系人可以通过世界日志（LoTW）进行确认？

1. Special event contacts between stations in the US 美国各电视台之间的特殊活动联系
2. Contacts between a US station and a non-US station 美国电台和非美国电台之间的联系方式
3. Contacts for Worked All States credit Worked All States信贷联系人
4. All these choices are correct 所有这些选择都是正确的

E2C09. What type of equipment is commonly used to implement an amateur radio mesh network? 什么类型的设备通常用于实现业余无线电网状网络？

1. A 2-meter VHF transceiver with a 1,200-baud modem 一个带1200波特调制解调器的2米甚高频收发器
2. A computer running EchoLink to provide interface from the radio to the internet 一台运行EchoLink的计算机，用于提供从收音机到互联网的接口
3. A wireless router running custom firmware 运行自定义固件的无线路由器
4. A 440 MHz transceiver with a 9,600-baud modem 带9600波特调制解调器的440 MHz收发器

E2C10. Why do DX stations often transmit and receive on different frequencies? 为什么DX电台经常在不同的频率上进行发射和接收？

1. Because the DX station may be transmitting on a frequency that is prohibited to some responding stations 因为DX站可能在某些响应站禁止的频率上进行传输
2. To separate the calling stations from the DX station 将呼叫站与DX站分开
3. To improve operating efficiency by reducing interference 通过减少干扰来提高运行效率
4. All these choices are correct 所有这些选择都是正确的

E2C11. How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup? 当你在比赛期间或在堆积中试图联系DX电台时，你通常应该如何识别你的电台？

1. Send your full call sign once or twice 发送一到两次完整的呼号
2. Send only the last two letters of your call sign until you make contact 只发送呼号的最后两个字母，直到您取得联系
3. Send your full call sign and grid square 发送完整的呼号和方格
4. Send the call sign of the DX station three times, the words “this is,” then your call sign three times 发送DX电台的呼号三次，上面写着“这就是”，然后发送呼号三遍

E2C12. What indicates the delay between a control operator action and the corresponding change in the transmitted signal? 什么表示控制操作员动作与传输信号的相应变化之间的延迟？

1. Jitter 抖动
2. Hang time 挂起时间
3. Latency 延迟
4. Anti-VOX 抗VOX

E2D01. Which of the following digital modes is designed for meteor scatter communications? 以下哪种数字模式是为流星散射通信设计的？

1. WSPR
2. MSK144
3. Hellschreiber
4. APRS 四月

E2D02. What information replaces signal-to-noise ratio when using the FT8 or FT4 modes in a VHF contest? 在甚高频比赛中使用FT8或FT4模式时，哪些信息取代了信噪比？

1. RST report RST报告
2. State abbreviation 州缩写
3. Serial number 序列号
4. Grid square 网格正方形

E2D03. Which of the following digital modes is designed for EME communications? 以下哪种数字模式是为EME通信设计的？

1. MSK144
2. PACTOR III 协定三
3. WSPR
4. Q65

E2D04. What technology is used for real-time tracking of balloons carrying amateur radio transmitters? 什么技术用于实时跟踪携带业余无线电发射机的气球？

1. FT8 英尺8
2. Bandwidth compressed LORAN 带宽压缩LORAN
3. APRS 四月
4. PACTOR III 协定三

E2D05. What is the characteristic of the JT65 mode? JT65模式的特点是什么？

1. Uses only a 65 Hz bandwidth 仅使用65 Hz带宽
2. Decodes signals with a very low signal-to-noise ratio 解码信噪比非常低的信号
3. Symbol rate is 65 baud 符号速率为65波特
4. Permits fast-scan TV transmissions over narrow bandwidth 允许在窄带宽上进行快速扫描电视传输

E2D06. Which of the following is a method for establishing EME contacts? 以下哪种方法是建立紧急紧急紧急事件联系人的方法？

1. Time-synchronous transmissions alternating between stations 站点之间交替的时间同步传输
2. Storing and forwarding digital messages 存储和转发数字消息
3. Judging optimum transmission times by monitoring beacons reflected from the moon 通过监测月球反射的信标判断最佳传输时间
4. High-speed CW identification to avoid fading 避免衰落的高速连续波识别

E2D07. What digital protocol is used by APRS? APRS使用什么数字协议？

1. PACTOR 协定者
2. QAM 正交振幅调制
3. AX.25
4. AMTOR

E2D08. What type of packet frame is used to transmit APRS beacon data? 什么类型的分组帧用于传输APRS信标数据？

1. Acknowledgement 确认
2. Burst 爆发
3. Unnumbered Information 未编号的信息
4. Connect 连接

E2D09. What type of modulation is used by JT65? JT65使用哪种类型的调制？

1. Multitone AFSK 多音AFSK
2. PSK 相移键控
3. RTTY 无线电传
4. QAM 正交振幅调制

E2D10. What does the packet path WIDE3-1 designate? 数据包路径WIDE3-1指定了什么？

1. Three stations are allowed on frequency, one transmitting at a time 频率上允许有三个电台，一次一个电台发射
2. Three subcarriers are permitted, subcarrier one is being used 允许使用三个子载波，正在使用一个子载波
3. Three digipeater hops are requested with one remaining 请求三个digipeater跃点，剩余一个
4. Three internet gateway stations may receive one transmission 三个互联网网关站可以接收一次传输

E2D11. How do APRS stations relay data? APRS站如何中继数据？

1. By packet ACK/NAK relay 通过分组ACK/NAK中继
2. By C4FM repeaters 通过C4FM中继器
3. By DMR repeaters 通过DMR中继器
4. By packet digipeaters 通过数据包数字化器

E2E01. Which of the following types of modulation is used for data emissions below 30 MHz? 以下哪种类型的调制用于30 MHz以下的数据发射？

1. DTMF tones modulating an FM signal DTMF音调调制调频信号
2. FSK 频移键控
3. Pulse modulation 脉冲调制
4. Spread spectrum 扩频

E2E02. Which of the following synchronizes WSJT-X digital mode transmit/receive timing? 以下哪项同步WSJT-X数字模式发送/接收定时？

1. Alignment of frequency shifts 频率偏移的校准
2. Synchronization of computer clocks 计算机时钟的同步
3. Sync-field transmission 同步字段传输
4. Sync-pulse timing 同步脉冲定时

E2E03. To what does the "4" in FT4 refer? FT4中的“4”指的是什么？

1. Multiples of 4 bits of user information 4位用户信息的倍数
2. Four-tone continuous-phase frequency shift keying 四音连续相移频键控
3. Four transmit/receive cycles per minute 每分钟四个发送/接收周期
4. All these choices are correct 所有这些选择都是正确的

E2E04. Which of the following is characteristic of the FST4 mode? 以下哪项是FST4模式的特征？

1. Four-tone Gaussian frequency shift keying 四音调高斯频移键控
2. Variable transmit/receive periods 可变发射/接收周期
3. Seven different tone spacings 七种不同的音调间距
4. All these choices are correct 所有这些选择都是正确的

E2E05. Which of these digital modes does not support keyboard-to-keyboard operation? 以下哪种数字模式不支持键盘对键盘操作？

1. WSPR
2. RTTY 无线电传
3. PSK31
4. MFSK16

E2E06. What is the length of an FT8 transmission cycle? FT8传输周期的长度是多少？

1. It varies with the amount of data 它随数据量的不同而变化
2. 8 seconds 8秒
3. 15 seconds 15秒
4. 30 seconds 30秒

E2E07. How does Q65 differ from JT65? Q65与JT65有何不同？

1. Keyboard-to keyboard operation is supported 支持键盘对键盘操作
2. Quadrature modulation is used 使用正交调制
3. Multiple receive cycles are averaged 对多个接收周期取平均值
4. All these choices are correct 所有这些选择都是正确的

E2E08. Which of the following HF digital modes can be used to transfer binary files? 以下哪种HF数字模式可用于传输二进制文件？

1. PSK31
2. PACTOR 协定者
3. RTTY 无线电传
4. AMTOR

E2E09. Which of the following HF digital modes uses variable-length character coding? 以下哪种HF数字模式使用可变长度字符编码？

1. RTTY 无线电传
2. PACTOR 协定者
3. MT63
4. PSK31

E2E10. Which of these digital modes has the narrowest bandwidth? 以下哪种数字模式的带宽最窄？

1. MFSK16
2. 170 Hz shift, 45-baud RTTY 170 Hz移位，45波特RTTY
3. FT8 英尺8
4. PACTOR IV

E2E11. What is the difference between direct FSK and audio FSK? 直接FSK和音频FSK之间的区别是什么？

1. Direct FSK modulates the transmitter VFO 直接FSK调制发射机VFO
2. Direct FSK occupies less bandwidth 直接FSK占用的带宽较少
3. Direct FSK can transmit higher baud rates 直接FSK可以传输更高的波特率
4. All these choices are correct 所有这些选择都是正确的

E2E12. How do ALE stations establish contact? ALE电台如何建立联系？

1. ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received ALE不断扫描频率列表，当收到指定的呼号时激活无线电
2. ALE radios monitor an internet site for the frequency they are being paged on ALE无线电监控互联网站点的寻呼频率
3. ALE radios send a constant tone code to establish a frequency for future use ALE无线电发送一个恒定音调代码，以建立未来使用的频率
4. ALE radios activate when they hear their signal echoed by back scatter ALE无线电在听到反向散射回波信号时激活

E2E13. Which of these digital modes has the highest data throughput under clear communication conditions? 在清晰的通信条件下，以下哪种数字模式的数据吞吐量最高？

1. MFSK16
2. 170 Hz shift, 45 baud RTTY 170 Hz移位，45波特RTTY
3. FT8 英尺8
4. PACTOR IV

E3A01. What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME? EME通信的两个站之间沿地球表面测得的近似最大间距是多少？

1. 2,000 miles, if the moon is at perigee 2000英里，如果月球在近地点
2. 2,000 miles, if the moon is at apogee 2000英里，如果月球在远地点
3. 5,000 miles, if the moon is at perigee 5000英里，如果月球在近地点
4. 12,000 miles, if the moon is “visible” by both stations 12000英里，如果两个站都能“看到”月球

E3A02. What characterizes libration fading of an EME signal? 电磁辐射信号的平动衰落特征是什么？

1. A slow change in the pitch of the CW signal CW信号音调的缓慢变化
2. A fluttery, irregular fading 飘动的、不规则的褪色
3. A gradual loss of signal as the sun rises 太阳升起时信号逐渐消失
4. The returning echo is several hertz lower in frequency than the transmitted signal 返回的回波频率比发送的信号低几赫兹

E3A03. When scheduling EME contacts, which of these conditions will generally result in the least path loss? 在调度EME联系人时，这些条件中的哪一个通常会导致最小的路径损耗？

1. When the Moon is at perigee 当月球在近地点时
2. When the Moon is full 当月亮满月时
3. When the Moon is at apogee 当月球在远地点时
4. When the MUF is above 30 MHz 当MUF高于30 MHz时

E3A04. In what direction does an electromagnetic wave travel? 电磁波的传播方向是什么？

1. It depends on the phase angle of the magnetic field 这取决于磁场的相位角
2. It travels parallel to the electric and magnetic fields 它平行于电场和磁场传播
3. It depends on the phase angle of the electric field 它取决于电场的相位角
4. It travels at a right angle to the electric and magnetic fields 它与电场和磁场成直角传播

E3A05. How are the component fields of an electromagnetic wave oriented? 电磁波的分量场是如何定向的？

1. They are parallel 它们是平行的
2. They are tangential 它们是相切的
3. They are at right angles 它们成直角
4. They are 90 degrees out of phase 它们相位相差90度

E3A06. What should be done to continue a long-distance contact when the MUF for that path decreases due to darkness? 当该路径的MUF因黑暗而降低时，应如何继续进行长距离接触？

1. Switch to a higher frequency HF band 切换到更高频率的HF波段
2. Switch to a lower frequency HF band 切换到低频HF波段
3. Change to an antenna with a higher takeoff angle 换成起飞角度更高的天线
4. Change to an antenna with greater beam width 更改为波束宽度更大的天线

E3A07. Atmospheric ducts capable of propagating microwave signals often form over what geographic feature? 能够传播微波信号的大气管道通常在什么地理特征上形成？

1. Mountain ranges 山脉
2. Stratocumulus clouds 层积云
3. Large bodies of water 大型水体
4. Nimbus clouds Nimbus云

E3A08. When a meteor strikes the Earth’s atmosphere, a linear ionized region is formed at what region of the ionosphere? 当流星撞击地球大气层时，电离层的哪个区域会形成线性电离区？

1. The E region E区域
2. The F1 region F1区域
3. The F2 region F2区域
4. The D region D区域

E3A09. Which of the following frequency ranges is most suited for meteor-scatter communications? 以下哪个频率范围最适合流星散射通信？

1. 1.8 MHz - 1.9 MHz 1.8兆赫-1.9兆赫
2. 10 MHz - 14 MHz 10兆赫-14兆赫
3. 28 MHz - 148 MHz 28兆赫-148兆赫
4. 220 MHz - 450 MHz 220兆赫-450兆赫

E3A10. What determines the speed of electromagnetic waves through a medium? 是什么决定了电磁波通过介质的速度？

1. Resistance and reactance 电阻和电抗
2. Evanescence Evancence
3. Birefringence 双折射
4. The index of refraction 折射率

E3A11. What is a typical range for tropospheric duct propagation of microwave signals? 微波信号的对流层导管传播的典型范围是多少？

1. 10 miles to 50 miles 10英里至50英里
2. 100 miles to 300 miles 100英里至300英里
3. 1,200 miles 1200英里
4. 2,500 miles 2500英里

E3A12. What is most likely to result in auroral propagation? 什么最有可能导致极光传播？

1. Meteor showers 流星雨
2. Quiet geomagnetic conditions 安静的地磁条件
3. Severe geomagnetic storms 强烈地磁风暴
4. Extreme low-pressure areas in polar regions 极地的极端低压区

E3A13. Which of these emission modes is best for auroral propagation? 以下哪种发射模式最适合极光传播？

1. CW 连续波
2. SSB
3. FM 调频
4. RTTY 无线电传

E3A14. What are circularly polarized electromagnetic waves? 什么是圆极化电磁波？

1. Waves with an electric field bent into a circular shape 电场弯曲成圆形的波
2. Waves with rotating electric and magnetic fields 具有旋转电场和磁场的波
3. Waves that circle Earth 环绕地球的波浪
4. Waves produced by a loop antenna 环形天线产生的波

E3B01. Where is transequatorial propagation (TEP) most likely to occur? 跨赤道传播（TEP）最有可能发生在哪里？

1. Between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator 在垂直于地磁赤道的路径上相距2000英里至3000英里的点之间
2. Between points located 1,500 miles to 2,000 miles apart on the geomagnetic equator 地磁赤道上相距1500英里至2000英里的点之间
3. Between points located at each other’s antipode 位于彼此对极的点之间
4. Through the region where the terminator crosses the geographic equator 穿过终止符穿过地理赤道的区域

E3B02. What is the approximate maximum range for signals using transequatorial propagation? 使用跨赤道传播的信号的近似最大范围是多少？

1. 1,000 miles 1000英里
2. 2,500 miles 2500英里
3. 5,000 miles 5000英里
4. 7,500 miles 7500英里

E3B03. At what time of day is transequatorial propagation most likely to occur? 跨赤道传播最有可能发生在一天中的什么时候？

1. Morning 早晨
2. Noon 正午
3. Afternoon or early evening 下午或傍晚
4. Late at night 深夜

E3B04. What are “extraordinary” and “ordinary” waves? 什么是“非同寻常”和“普通”的波浪？

1. Extraordinary waves exhibit rare long-skip propagation, compared to ordinary waves, which travel shorter distances 与传播距离较短的普通波相比，特殊波表现出罕见的长跳传播
2. Independently propagating, elliptically polarized waves created in the ionosphere 电离层中产生的独立传播的椭圆偏振波
3. Long-path and short-path waves 长程波和短程波
4. Refracted rays and reflected waves 折射光线和反射波

E3B05. Which of the following paths is most likely to support long-distance propagation on 160 meters? 以下哪种路径最有可能支持160米的长距离传播？

1. A path entirely in sunlight 一条完全在阳光下的小路
2. Paths at high latitudes 高纬度地区的路径
3. A direct north-south path 一条直接的南北路径
4. A path entirely in darkness 一条完全黑暗的道路

E3B06. On which of the following amateur bands is long-path propagation most frequent? 以下哪一个业余波段的长路径传播最频繁？

1. 160 meters and 80 meters 160米和80米
2. 40 meters and 20 meters 40米和20米
3. 10 meters and 6 meters 10米和6米
4. 6 meters and 2 meters 6米和2米

E3B07. What effect does lowering a signal’s transmitted elevation angle have on ionospheric HF skip propagation? 降低信号的发射仰角对电离层HF跳跃传播有什么影响？

1. Faraday rotation becomes stronger 法拉第旋转变强
2. The MUF decreases MUF降低
3. The distance covered by each hop increases 每次跳跃的距离都会增加
4. The critical frequency increases 临界频率增加

E3B08. How does the maximum range of ground-wave propagation change when the signal frequency is increased? 当信号频率增加时，地波传播的最大范围如何变化？

1. It stays the same 它保持不变
2. It increases 它增加了
3. It decreases 它减少了
4. It peaks at roughly 8 MHz 它的峰值大约为8 MHz

E3B09. At what time of year is sporadic-E propagation most likely to occur? 孢子虫E最有可能在一年中的什么时候繁殖？

1. Around the solstices, especially the summer solstice 至日前后，尤其是夏至
2. Around the solstices, especially the winter solstice 冬至前后，尤其是冬至
3. Around the equinoxes, especially the spring equinox 春分前后，尤其是春分
4. Around the equinoxes, especially the fall equinox 春分前后，尤其是秋分

E3B10. What is the effect of chordal-hop propagation? 弦跳传播的效果是什么？

1. The signal experiences less loss compared to multi-hop propagation, which uses Earth as a reflector 与使用地球作为反射器的多跳传播相比，该信号的损耗更小
2. The MUF for chordal-hop propagation is much lower than for normal skip propagation 弦跳跃传播的MUF比正常跳跃传播的要低得多
3. Atmospheric noise is reduced in the direction of chordal-hop propagation 大气噪声在弦跳传播方向上减少
4. Signals travel faster along ionospheric chords 信号沿电离层弦传播得更快

E3B11. At what time of day is sporadic-E propagation most likely to occur? 孢子虫E最有可能在一天中的什么时候传播？

1. Between midnight and sunrise 午夜到日出之间
2. Between sunset and midnight 日落到午夜之间
3. Between sunset and sunrise 日落和日出之间
4. Between sunrise and sunset 日出和日落之间

E3B12. What is chordal-hop propagation? 什么是弦跳传播？

1. Propagation away from the great circle bearing between stations 远离大圆轴承的传播
2. Successive ionospheric refractions without an intermediate reflection from the ground 连续电离层折射，没有来自地面的中间反射
3. Propagation across the geomagnetic equator 地磁赤道上的传播
4. Signals reflected back toward the transmitting station 反射回发射站的信号

E3B13. What type of polarization is supported by ground-wave propagation? 地波传播支持哪种类型的极化？

1. Vertical 竖的
2. Horizontal 水平的
3. Circular 圆形的
4. Elliptical 椭圆形

E3C01. What is the cause of short-term radio blackouts? 是什么原因导致短期无线电中断？

1. Coronal mass ejections 日冕物质抛射
2. Sunspots on the solar equator 太阳赤道上的太阳黑子
3. North-oriented interplanetary magnetic field 北向行星际磁场
4. Solar flares 太阳耀斑

E3C02. What is indicated by a rising A-index or K-index? a指数或K指数的上升表明了什么？

1. Increasing disturbance of the geomagnetic field 地磁场扰动加剧
2. Decreasing disturbance of the geomagnetic field 减少地磁场的扰动
3. Higher levels of solar UV radiation 更高水平的太阳紫外线辐射
4. An increase in the critical frequency 临界频率的增加

E3C03. Which of the following signal paths is most likely to experience high levels of absorption when the A-index or K-index is elevated? 当A指数或K指数升高时，以下哪种信号路径最有可能经历高水平的吸收？

1. Transequatorial 跨赤道
2. Through the auroral oval 穿过极光椭圆
3. Sporadic-E 偶发E层
4. NVIS NVIS公司

E3C04. What does the value of Bz (B sub z) represent? Bz（B sub z）的值代表什么？

1. Geomagnetic field stability 地磁场稳定性
2. Critical frequency for vertical transmissions 垂直传输的临界频率
3. North-south strength of the interplanetary magnetic field 行星际磁场的南北强度
4. Duration of long-delayed echoes 长延迟回波的持续时间

E3C05. What orientation of Bz (B sub z) increases the likelihood that charged particles from the Sun will cause disturbed conditions? Bz（B sub z）的哪个方向增加了来自太阳的带电粒子引起扰动条件的可能性？

1. Southward 向南
2. Northward 向北
3. Eastward 向东
4. Westward 向西

E3C06. How does the VHF/UHF radio horizon compare to the geographic horizon? 甚高频/超高频无线电地平线与地理地平线相比如何？

1. It is approximately 15 percent farther 它大约远了15%
2. It is approximately 20 percent nearer 它大约接近20%
3. It is approximately 50 percent farther 它大约远了50%
4. They are approximately the same 它们大致相同

E3C07. Which of the following indicates the greatest solar flare intensity? 以下哪一项表明太阳耀斑强度最大？

1. Class A A类
2. Class Z Z类
3. Class M M级
4. Class X X类

E3C08. Which of the following is the space-weather term for an extreme geomagnetic storm? 以下哪一项是极端地磁风暴的空间天气术语？

1. B9
2. X5
3. M9
4. G5 G5型

E3C09. What type of data is reported by amateur radio propagation reporting networks? 业余无线电传播报告网络报告什么类型的数据？

1. Solar flux 太阳通量
2. Electric field intensity 电场强度
3. Magnetic declination 磁偏角
4. Digital-mode and CW signals 数字模式和CW信号

E3C10. What does the 304A solar parameter measure? 304A太阳能参数测量值是多少？

1. The ratio of X-ray flux to radio flux, correlated to sunspot number 与太阳黑子数量相关的X射线通量与无线电通量的比率
2. UV emissions at 304 angstroms, correlated to the solar flux index 304埃的紫外线辐射，与太阳通量指数相关
3. The solar wind velocity at an angle of 304 degrees from the solar equator, correlated to geomagnetic storms 与地磁风暴相关的与太阳赤道成304度角的太阳风速
4. The solar emission at 304 GHz, correlated to X-ray flare levels 304千兆赫的太阳辐射，与X射线耀斑水平相关

E3C11. What does VOACAP software model? VOACAP软件模型是什么？

1. AC voltage and impedance 交流电压和阻抗
2. VHF radio propagation 甚高频无线电传播
3. HF propagation HF传播
4. AC current and impedance 交流电流和阻抗

E3C12. Which of the following is indicated by a sudden rise in radio background noise across a large portion of the HF spectrum? 在高频频谱的很大一部分中，无线电背景噪声的突然上升表明了以下哪一项？

1. A temperature inversion has occurred 出现温度反转
2. A coronal mass ejection impact or a solar flare has occurred 发生了日冕物质抛射撞击或太阳耀斑
3. Transequatorial propagation on 6 meters is likely 可能在6米处传播
4. Long-path propagation on the higher HF bands is likely 高频带上的长路径传播很可能

E4A01. Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope? 以下哪项限制了可以在数字示波器上准确显示的最高频率信号？

1. Sampling rate of the analog-to-digital converter 模数转换器的采样率
2. Analog-to-digital converter reference frequency 模数转换器参考频率
3. Q of the circuit 电路的Q
4. All these choices are correct 所有这些选择都是正确的

E4A02. Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes? 频谱分析仪在垂直轴和水平轴上显示以下哪个参数？

1. Signal amplitude and time 信号幅度和时间
2. Signal amplitude and frequency 信号幅度和频率
3. SWR and frequency SWR和频率
4. SWR and time SWR和时间

E4A03. Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter? 以下哪种测试仪器用于显示SSB发射机产生的杂散信号和/或互调失真产物？

1. Differential resolver 差动分解器
2. Spectrum analyzer 频谱分析仪
3. Logic analyzer 逻辑分析仪
4. Network analyzer 网络分析仪

E4A04. How is compensation of an oscilloscope probe performed? 示波器探头的补偿是如何进行的？

1. A square wave is displayed, and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible 显示方波，并调整探头，直到显示的波的水平部分尽可能接近平坦
2. A high frequency sine wave is displayed, and the probe is adjusted for maximum amplitude 显示高频正弦波，并调整探头的最大振幅
3. A frequency standard is displayed, and the probe is adjusted until the deflection time is accurate 显示频率标准，并调整探头，直到偏转时间准确为止
4. A DC voltage standard is displayed, and the probe is adjusted until the displayed voltage is accurate 显示直流电压标准，并调整探头，直到显示的电压准确为止

E4A05. What is the purpose of using a prescaler with a frequency counter? 使用带频率计数器的预分频器的目的是什么？

1. Amplify low-level signals for more accurate counting 放大低电平信号以实现更准确的计数
2. Multiply a higher frequency signal so a low-frequency counter can display the operating frequency 将较高频率的信号相乘，使低频计数器可以显示工作频率
3. Prevent oscillation in a low-frequency counter circuit 防止低频计数器电路中的振荡
4. Reduce the signal frequency to within the counter's operating range 将信号频率降低到计数器的工作范围内

E4A06. What is the effect of aliasing on a digital oscilloscope when displaying a waveform? 显示波形时，混叠对数字示波器的影响是什么？

1. A false, jittery low-frequency version of the waveform is displayed 显示虚假的、抖动的低频波形版本
2. The waveform DC offset will be inaccurate 波形直流偏移将不准确
3. Calibration of the vertical scale is no longer valid 垂直刻度的校准不再有效
4. Excessive blanking occurs, which prevents display of the waveform 出现过多的消隐，从而阻止波形的显示

E4A07. Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge? 与SWR电桥相比，以下哪项是使用天线分析仪的优势？

1. Antenna analyzers automatically tune your antenna for resonance 天线分析仪自动调整天线以产生谐振
2. Antenna analyzers compute SWR and impedance automatically 天线分析仪自动计算SWR和阻抗
3. Antenna analyzers display a time-varying representation of the modulation envelope 天线分析仪显示调制包络的时变表示
4. All these choices are correct 所有这些选择都是正确的

E4A08. Which of the following is used to measure SWR? 以下哪项用于测量SWR？

1. Directional wattmeter 定向瓦特计
2. Vector network analyzer 矢量网络分析仪
3. Antenna analyzer 天线分析仪
4. All these choices are correct 所有这些选择都是正确的

E4A09. Which of the following is good practice when using an oscilloscope probe? 使用示波器探头时，以下哪项是良好的做法？

1. Minimize the length of the probe's ground connection 尽可能缩短探针接地连接的长度
2. Never use a high-impedance probe to measure a low-impedance circuit 切勿使用高阻抗探针测量低阻抗电路
3. Never use a DC-coupled probe to measure an AC circuit 切勿使用直流耦合探针测量交流电路
4. All these choices are correct 所有这些选择都是正确的

E4A10. Which trigger mode is most effective when using an oscilloscope to measure a linear power supply’s output ripple? 当使用示波器测量线性电源的输出纹波时，哪种触发模式最有效？

1. Single-shot 单次拍摄
2. Edge 边
3. Level 数量
4. Line 线

E4A11. Which of the following can be measured with an antenna analyzer? 以下哪项可以用天线分析仪进行测量？

1. Velocity factor 速度系数
2. Cable length 电缆长度
3. Resonant frequency of a tuned circuit 调谐电路的谐振频率
4. All these choices are correct 所有这些选择都是正确的

E4B01. Which of the following factors most affects the accuracy of a frequency counter? 以下哪个因素对频率计数器的精度影响最大？

1. Input attenuator accuracy 输入衰减器精度
2. Time base accuracy 时基精度
3. Decade divider accuracy 十进制除法器精度
4. Temperature coefficient of the logic 逻辑的温度系数

E4B02. What is the significance of voltmeter sensitivity expressed in ohms per volt? 以欧姆/伏特表示的电压表灵敏度的意义是什么？

1. The full scale reading of the voltmeter multiplied by its ohms per volt rating is the input impedance of the voltmeter 电压表的满刻度读数乘以每伏额定值的欧姆即为电压表的输入阻抗
2. The reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test 以伏特为单位的读数乘以欧姆每伏特额定值将决定被测设备所消耗的功率
3. The reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit 以欧姆为单位的读数除以欧姆每伏额定值将决定施加到电路上的电压
4. The full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed 以安培为单位的满刻度读数除以每伏额定值的欧姆将决定所需分流器的大小

E4B03. Which S parameter is equivalent to forward gain? 哪个S参数等效于正向增益？

1. S11 第11条
2. S12
3. S21
4. S22

E4B04. Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)? 哪个S参数表示输入端口回波损耗或反射系数（相当于VSWR）？

1. S11 第11条
2. S12
3. S21
4. S22

E4B05. What three test loads are used to calibrate an RF vector network analyzer? 哪三种测试负载用于校准RF矢量网络分析仪？

1. 50 ohms, 75 ohms, and 90 ohms 50欧姆、75欧姆和90欧姆
2. Short circuit, open circuit, and 50 ohms 短路、断路和50欧姆
3. Short circuit, open circuit, and resonant circuit 短路、断路和谐振电路
4. 50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable 50欧姆通过1/8波长、1/4波长和1/2波长的同轴电缆

E4B06. How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power? 当连接在发射机和终端负载之间的定向功率表读取100瓦正向功率和25瓦反射功率时，负载吸收了多少功率？

1. 100 watts 100瓦
2. 125 watts 125瓦
3. 112.5 watts 112.5瓦
4. 75 watts 75瓦

E4B07. What do the subscripts of S parameters represent? S参数的下标代表什么？

1. The port or ports at which measurements are made 进行测量的端口
2. The relative time between measurements 测量之间的相对时间
3. Relative quality of the data 数据的相对质量
4. Frequency order of the measurements 测量的频率顺序

E4B08. Which of the following can be used to determine the Q of a series-tuned circuit? 以下哪项可用于确定串联调谐电路的Q？

1. The ratio of inductive reactance to capacitive reactance 感抗与容抗之比
2. The frequency shift 频率偏移
3. The bandwidth of the circuit's frequency response 电路频率响应的带宽
4. The resonant frequency of the circuit 电路的谐振频率

E4B09. Which of the following can be measured by a two-port vector network analyzer? 以下哪项可以通过双端口矢量网络分析仪进行测量？

1. Phase noise 相位噪声
2. Filter frequency response 滤波器频率响应
3. Pulse rise time 脉冲上升时间
4. Forward power 正向功率

E4B10. Which of the following methods measures intermodulation distortion in an SSB transmitter? 以下哪种方法测量SSB发射机中的互调失真？

1. Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer 使用具有非谐波相关频率的两个RF信号调制发射器，并使用频谱分析仪观察RF输出
2. Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer 使用具有非谐波相关频率的两个AF信号调制发射器，并使用频谱分析仪观察RF输出
3. Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter 使用具有谐波相关频率的两个AF信号调制发射器，并使用峰值读数瓦特计观察RF输出
4. Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer 使用具有谐波相关频率的两个RF信号调制发射器，并用逻辑分析仪观察RF输出

E4B11. Which of the following can be measured with a vector network analyzer? 以下哪项可以用矢量网络分析仪进行测量？

1. Input impedance 输入阻抗
2. Output impedance 输出阻抗
3. Reflection coefficient 反射系数
4. All these choices are correct 所有这些选择都是正确的

E4C01. What is an effect of excessive phase noise in an SDR receiver’s master clock oscillator? SDR接收机主时钟振荡器中过多的相位噪声会产生什么影响？

1. It limits the receiver’s ability to receive strong signals 它限制了接收器接收强信号的能力
2. It can affect the receiver’s frequency calibration 它会影响接收器的频率校准
3. It decreases the receiver’s third-order intercept point 它降低了接收器的三阶截点
4. It can combine with strong signals on nearby frequencies to generate interference 它可以与附近频率上的强信号结合产生干扰

E4C02. Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals? 以下哪种接收器电路可以有效地消除强带外信号的干扰？

1. A front-end filter or preselector 前端过滤器或预选器
2. A narrow IF filter 窄中频滤波器
3. A notch filter 陷波滤波器
4. A properly adjusted product detector 经过适当调整的产品检测器

E4C03. What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency? 在调频接收机中，一个信号被同一频率上的另一个更强信号抑制的术语是什么？

1. Desensitization 脱敏作用
2. Cross-modulation interference 交叉调制干扰
3. Capture effect 捕获效果
4. Frequency discrimination 频率辨别

E4C04. What is the noise figure of a receiver? 接收器的噪声系数是多少？

1. The ratio of atmospheric noise to phase noise 大气噪声与相位噪声之比
2. The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network 以赫兹为单位的噪声带宽与电阻网络的理论带宽之比
3. The ratio in dB of the noise generated in the receiver to atmospheric noise 接收器中产生的噪声与大气噪声之比（dB）
4. The ratio in dB of the noise generated by the receiver to the theoretical minimum noise 接收器产生的噪声与理论最小噪声之比（dB）

E4C05. What does a receiver noise floor of -174 dBm represent? -174dBm的接收机本底噪声代表什么？

1. The receiver noise is 6 dB above the theoretical minimum 接收器噪声比理论最小值高出6 dB
2. The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature 室温下完美接收器输入端1 Hz带宽的理论噪声
3. The noise figure of a 1 Hz bandwidth receiver 1 Hz带宽接收器的噪声系数
4. The receiver noise is 3 dB above theoretical minimum 接收器噪声比理论最小值高出3 dB

E4C06. How much does increasing a receiver’s bandwidth from 50 Hz to 1,000 Hz increase the receiver’s noise floor? 将接收器的带宽从50 Hz增加到1000 Hz会在多大程度上增加接收器的本底噪声？

1. 3 dB 3分贝
2. 5 dB 5分贝
3. 10 dB 10分贝
4. 13 dB 13分贝

E4C07. What does the MDS of a receiver represent? 接收器的MDS代表什么？

1. The meter display sensitivity 仪表显示灵敏度
2. The minimum discernible signal 最小可辨别信号
3. The modulation distortion specification 调制失真规格
4. The maximum detectable spectrum 最大可检测光谱

E4C08. An SDR receiver is overloaded when input signals exceed what level? 当输入信号超过什么水平时，SDR接收器过载？

1. One-half of the maximum sample rate 最大采样率的一半
2. One-half of the maximum sampling buffer size 最大采样缓冲区大小的一半
3. The maximum count value of the analog-to-digital converter 模数转换器的最大计数值
4. The reference voltage of the analog-to-digital converter 模数转换器的参考电压

E4C09. Which of the following choices is a good reason for selecting a high IF for a superheterodyne HF or VHF communications receiver? 以下哪种选择是为超外差HF或VHF通信接收机选择高IF的好理由？

1. Fewer components in the receiver 接收器中的组件较少
2. Reduced drift 减少漂移
3. Easier for front-end circuitry to eliminate image responses 前端电路更容易消除图像响应
4. Improved receiver noise figure 改进的接收器噪声系数

E4C10. What is an advantage of having a variety of receiver bandwidths from which to select? 有多种接收机带宽可供选择的优势是什么？

1. The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity 可以调整射频放大器的噪声系数以匹配调制类型，从而提高接收器的灵敏度
2. Receiver power consumption can be reduced when wider bandwidth is not required 当不需要更宽的带宽时，可以降低接收器功耗
3. Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference 可以将接收带宽设置为与调制带宽相匹配，从而最大限度地提高信噪比并最大限度地减少干扰
4. Multiple frequencies can be received simultaneously if desired 如果需要，可以同时接收多个频率

E4C11. Why does input attenuation reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio? 为什么输入衰减可以减少低频HF频带上的接收器过载，而对信噪比几乎没有影响？

1. The attenuator has a low-pass filter to increase the strength of lower frequency signals 衰减器有一个低通滤波器，用于增加低频信号的强度
2. The attenuator has a noise filter to suppress interference 衰减器有一个噪声滤波器来抑制干扰
3. Signals are attenuated separately from the noise 信号与噪声分开衰减
4. Atmospheric noise is generally greater than internally generated noise even after attenuation 即使在衰减之后，大气噪声通常也大于内部产生的噪声

E4C12. How does a narrow-band roofing filter affect receiver performance? 窄带屋顶滤波器如何影响接收机性能？

1. It improves sensitivity by reducing front-end noise 它通过减少前端噪声来提高灵敏度
2. It improves intelligibility by using low Q circuitry to reduce ringing 它通过使用低Q电路来减少振铃，从而提高清晰度
3. It improves blocking dynamic range by attenuating strong signals near the receive frequency 它通过衰减接收频率附近的强信号来改善阻塞动态范围
4. All these choices are correct 所有这些选择都是正确的

E4C13. What is reciprocal mixing? 什么是相互混合？

1. Two out-of-band signals mixing to generate an in-band spurious signal 两个带外信号混合以生成带内杂散信号
2. In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity 混频器中的同相信号抵消导致接收器灵敏度的损失
3. Two digital signals combining from alternate time slots 来自交替时隙的两个数字信号组合
4. Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals 本地振荡器相位噪声与相邻强信号混合，对所需信号产生干扰

E4C14. What is the purpose of the receiver IF Shift control? 接收机中频偏移控制的目的是什么？

1. To permit listening on a different frequency from the transmitting frequency 允许在与发射频率不同的频率上收听
2. To change frequency rapidly 快速更改频率
3. To reduce interference from stations transmitting on adjacent frequencies 减少在相邻频率上传输的电台的干扰
4. To tune in stations slightly off frequency without changing the transmit frequency 在不改变发射频率的情况下微调电台

E4D01. What is meant by the blocking dynamic range of a receiver? 接收器的阻塞动态范围是什么意思？

1. The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression 本底噪声与将导致1 dB增益压缩的输入信号电平之间的差值（dB）
2. The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other 将导致一个信号阻塞另一个信号的两个调频信号电平之间的最小差值（dB）
3. The difference in dB between the noise floor and the third-order intercept point 本底噪声和三阶截距点之间的差值（dB）
4. The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor 产生大于本底噪声的三阶互调产物的两个信号之间的最小差值（dB）

E4D02. Which of the following describes problems caused by poor dynamic range in a receiver? 以下哪一项描述了由接收器中较差的动态范围引起的问题？

1. Spurious signals caused by cross modulation and desensitization from strong adjacent signals 强相邻信号的交叉调制和脱敏引起的杂散信号
2. Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband 振荡器的不稳定性需要频繁的重新调谐，并失去恢复相对边带的能力
3. Poor weak signal reception caused by insufficient local oscillator injection 本地振荡器注入不足导致弱信号接收不良
4. Oscillator instability and severe audio distortion of all but the strongest received signals 振荡器不稳定，除最强接收信号外的所有信号都会出现严重的音频失真

E4D03. What creates intermodulation interference between two repeaters in close proximity? 是什么造成了两个中继器之间的互调干扰？

1. The output signals cause feedback in the final amplifier of one or both transmitters 输出信号在一个或两个发射器的最终放大器中引起反馈
2. The output signals mix in the final amplifier of one or both transmitters 输出信号在一个或两个发射器的最终放大器中混合
3. The input frequencies are harmonically related 输入频率是谐波相关的
4. The output frequencies are harmonically related 输出频率是谐波相关的

E4D04. Which of the following is used to reduce or eliminate intermodulation interference in a repeater caused by a nearby transmitter? 以下哪项用于减少或消除中继器中由附近发射机引起的互调干扰？

1. A band-pass filter in the feed line between the transmitter and receiver 发射机和接收机之间馈线中的带通滤波器
2. A properly terminated circulator at the output of the repeater’s transmitter 中继器发射机输出端适当端接的循环器
3. Utilizing a Class C final amplifier 使用C类末级放大器
4. Utilizing a Class D final amplifier 使用D类末级放大器

E4D05. What transmitter frequencies would create an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz? 当附近的电台在146.52 MHz上发射时，哪些发射机频率会在调谐到146.70 MHz的接收机中产生互调产物信号？

1. 146.34 MHz and 146.61 MHz 146.34 MHz和146.61 MHz
2. 146.88 MHz and 146.34 MHz 146.88兆赫和146.34兆赫
3. 146.10 MHz and 147.30 MHz 146.10兆赫和147.30兆赫
4. 146.30 MHz and 146.90 MHz 146.30 MHz和146.90 MHz

E4D06. What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency? 接收频率附近的强信号导致接收器灵敏度降低的术语是什么？

1. Reciprocal mixing 相互混合
2. Quieting 安静
3. Desensitization 脱敏作用
4. Cross modulation interference 交叉调制干扰

E4D07. Which of the following reduces the likelihood of receiver desensitization? 以下哪项降低了受试者脱敏的可能性？

1. Insert attenuation before the first RF stage 在第一个射频级之前插入衰减
2. Raise the receiver’s IF frequency 提高接收机的中频频率
3. Increase the receiver’s front-end gain 增加接收器的前端增益
4. Switch from fast AGC to slow AGC 从快速AGC切换到慢速AGC

E4D08. What causes intermodulation in an electronic circuit? 是什么导致了电子电路中的互调？

1. Negative feedback 非正面反馈
2. Lack of neutralization 缺乏中和作用
3. Nonlinear circuits or devices 非线性电路或设备
4. Positive feedback 积极反馈

E4D09. What is the purpose of the preselector in a communications receiver? 通信接收机中预选器的用途是什么？

1. To store frequencies that are often used 存储经常使用的频率
2. To provide broadband attenuation before the first RF stage to prevent intermodulation 在第一RF级之前提供宽带衰减以防止互调
3. To increase the rejection of signals outside the band being received 增加对接收频带外信号的抑制
4. To allow selection of the optimum RF amplifier device 选择最佳射频放大器设备

E4D10. What does a third-order intercept level of 40 dBm mean with respect to receiver performance? 就接收机性能而言，40 dBm的三阶截获电平意味着什么？

1. Signals less than 40 dBm will not generate audible third-order intermodulation products 小于40 dBm的信号不会产生可听见的三阶互调产物
2. The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products 接收器可以容忍高于本底噪声40dB的信号，而不会产生三阶互调产物
3. A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals 理论上，一对40dBm的输入信号将产生三阶互调产物，该互调产物具有与任一输入信号相同的输出幅度
4. A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal 一对1mW的输入信号将产生比输入信号强40dB的三阶互调产物

E4D11. Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products? 为什么在接收器内创建的奇数阶互调产品与其他产品相比特别令人感兴趣？

1. Odd-order products of two signals in the band being received are also likely to be within the band 正在接收的频带中的两个信号的奇数阶乘积也可能在频带内
2. Odd-order products are more likely to overload the IF filters 奇数阶产品更有可能使IF滤波器过载
3. Odd-order products are an indication of poor image rejection 奇数订单产品表明图像拒绝率低
4. Odd-order intermodulation produces three products for every input signal within the band of interest 奇数阶互调为感兴趣频带内的每个输入信号产生三个乘积

E4D12. What is the link margin in a system with a transmit power level of 100 W (+40 dBm), a system antenna gain of 10 dBi, a cable loss of 3 dB, a path loss of 136 dB, a receiver minimum discernable signal of -103 dBm, and a required signal-to-noise ratio of 6 dB? 在发射功率电平为100 W（+40 dBm）、系统天线增益为10 dBi、电缆损耗为3 dB、路径损耗为136 dB、接收器最小可分辨信号为-103 dBm、所需信噪比为6 dB的系统中，链路裕度是多少？

1. -8dB
2. -14dB -14分贝
3. +8dB
4. +14dB +14分贝

E4D13. What is the received signal level with a transmit power of 100 W (+40 dBm), a transmit antenna gain of 6 dBi, a receive antenna gain of 3 dBi, and a path loss of 100 dB? 发射功率为100W（+40dBm），发射天线增益为6dBi，接收天线增益为3dBi，路径损耗为100dB时，接收信号电平是多少？

1. -51 dBm
2. -54 dBm
3. -57 dBm
4. -60 dBm

E4D14. What power level does a receiver minimum discernible signal of -100 dBm represent? -100 dBm的接收器最小可辨别信号代表什么功率电平？

1. 100 microwatts 100微瓦
2. 0.1 microwatt 0.1微瓦
3. 0.001 microwatts 0.001微瓦
4. 0.1 picowatts 0.1皮瓦

E4E01. What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals? 当在接收CW信号时使用自动陷波滤波器（ANF）来去除干扰载波时，会出现什么问题？

1. Removal of the CW signal as well as the interfering carrier 去除CW信号和干扰载波
2. Any nearby signal passing through the DSP system will overwhelm the desired signal 任何通过DSP系统的附近信号都会淹没所需信号
3. Excessive ringing 振铃过大
4. All these choices are correct 所有这些选择都是正确的

E4E02. Which of the following types of noise can often be reduced by a digital noise reduction? 以下哪种类型的噪声通常可以通过数字降噪来降低？

1. Broadband white noise 宽带白噪声
2. Ignition noise 点火噪音
3. Power line noise 电源线噪声
4. All these choices are correct 所有这些选择都是正确的

E4E03. Which of the following types of noise are removed by a noise blanker? 以下哪种类型的噪声可以通过噪声消除器去除？

1. Broadband white noise 宽带白噪声
2. Impulse noise 脉冲噪声
3. Hum and buzz 哼哼
4. All these choices are correct 所有这些选择都是正确的

E4E04. How can conducted noise from an automobile battery charging system be suppressed? 如何抑制来自汽车电池充电系统的传导噪声？

1. By installing filter capacitors in series with the alternator leads 通过将滤波电容器与交流发电机导线串联安装
2. By installing a noise suppression resistor and a blocking capacitor at the battery 通过在蓄电池上安装噪声抑制电阻器和阻塞电容器
3. By installing a high-pass filter in series with the radio’s power lead and a low-pass filter in parallel with the antenna feed line 通过安装与收音机电源线串联的高通滤波器和与天线馈线并联的低通滤波器
4. By installing ferrite chokes on the charging system leads 通过在充电系统导线上安装铁氧体扼流圈

E4E05. What is used to suppress radio frequency interference from a line-driven AC motor? 什么是用来抑制线路驱动交流电机的射频干扰的？

1. A high-pass filter in series with the motor’s power leads 与电机电源线串联的高通滤波器
2. A brute-force AC-line filter in series with the motor’s power leads 与电机电源线串联的强力交流线路滤波器
3. A bypass capacitor in series with the motor’s field winding 与电机励磁绕组串联的旁路电容器
4. A bypass choke in parallel with the motor’s field winding 与电机励磁绕组并联的旁路扼流圈

E4E06. What type of electrical interference can be caused by computer network equipment? 计算机网络设备会引起什么类型的电气干扰？

1. A loud AC hum in the audio output of your station’s receiver 电台接收器的音频输出中有巨大的交流嗡嗡声
2. A clicking noise at intervals of a few seconds 每隔几秒钟就会发出咔嗒声
3. The appearance of unstable modulated or unmodulated signals at specific frequencies 在特定频率下出现不稳定的调制或未调制信号
4. A whining-type noise that continually pulses off and on 一种不断断断续续的呜呜声

E4E07. Which of the following can cause shielded cables to radiate or receive interference? 以下哪一项会导致屏蔽电缆辐射或接收干扰？

1. Low inductance ground connections at both ends of the shield 屏蔽两端的低电感接地连接
2. Common-mode currents on the shield and conductors 屏蔽和导体上的共模电流
3. Use of braided shielding material 编织屏蔽材料的使用
4. Tying all ground connections to a common point resulting in differential-mode currents in the shield 将所有接地连接连接到一个公共点，从而在屏蔽中产生差模电流

E4E08. What current flows equally on all conductors of an unshielded multiconductor cable? 无屏蔽多导体电缆的所有导体上的电流相等？

1. Differential-mode current 差模电流
2. Common-mode current 共模电流
3. Reactive current only 仅限无功电流
4. Magnetically-coupled current only 仅磁耦合电流

E4E09. What undesirable effect can occur when using a noise blanker? 使用噪声消除器时会产生什么不良影响？

1. Received audio in the speech range might have an echo effect 接收到的语音范围内的音频可能具有回声效果
2. The audio frequency bandwidth of the received signal might be compressed 接收信号的音频带宽可能被压缩
3. Strong signals may be distorted and appear to cause spurious emissions 强信号可能失真，并可能导致杂散发射
4. FM signals can no longer be demodulated 调频信号无法再解调

E4E10. Which of the following can create intermittent loud roaring or buzzing AC line interference? 以下哪种情况会产生间歇性的大声咆哮或嗡嗡声交流线路干扰？

1. Arcing contacts in a thermostatically controlled device 恒温控制设备中的电弧触点
2. A defective doorbell or doorbell transformer inside a nearby residence 附近住宅内有缺陷的门铃或门铃变压器
3. A malfunctioning illuminated advertising display 照明广告显示屏出现故障
4. All these choices are correct 所有这些选择都是正确的

E4E11. What could be the cause of local AM broadcast band signals combining to generate spurious signals on the MF or HF bands? 本地AM广播频带信号组合在MF或HF频带上产生杂散信号的原因是什么？

1. One or more of the broadcast stations is transmitting an over-modulated signal 一个或多个广播站正在发送过调制信号
2. Nearby corroded metal connections are mixing and reradiating the broadcast signals 附近被腐蚀的金属连接正在混合并重新辐射广播信号
3. You are receiving skywave signals from a distant station 你正在接收来自远处电台的天波信号
4. Your station receiver IF amplifier stage is overloaded 您的电台接收机中频放大器级过载

E4E12. What causes interference received as a series of carriers at regular intervals across a wide frequency range? 是什么导致在宽频率范围内以规则间隔接收到一系列载波的干扰？

1. Switch-mode power supplies 开关模式电源
2. Radar transmitters 雷达发射机
3. Wireless security camera transmitters 无线安全摄像头发射器
4. Electric fences 电动围栏

E4E13. Where should a station AC surge protector be installed? 电站交流浪涌保护器应安装在哪里？

1. At the AC service panel 在交流服务面板上
2. At an AC outlet 在AC插座处
3. On the single point ground panel 在单点接地面板上
4. On a ground rod outside the station 在车站外的接地棒上

E4E14. What is the purpose of a single point ground panel? 单点接地板的用途是什么？

1. Remove AC power in case of a short-circuit 短路时切断交流电源
2. Prevent common-mode transients in multi-wire systems 防止多线系统中的共模瞬态
3. Eliminate air gaps between protected and non-protected circuits 消除受保护电路和非受保护电路之间的气隙
4. Ensure all lightning protectors activate at the same time 确保所有防雷器同时启动

E5A01. What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit? 是什么原因导致串联RLC电路中电抗两端的电压高于施加到整个电路的电压？

1. Resonance 洪亮
2. Capacitance 电容
3. Low quality factor (Q) 低品质因数（Q）
4. Resistance 反对

E5A02. What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries, and C is 40 picofarads? 如果R是22欧姆，L是50微亨，C是40皮法，RLC电路的谐振频率是多少？

1. 44.72 MHz 44.72兆赫
2. 22.36 MHz 22.36兆赫
3. 3.56 MHz 3.56兆赫
4. 1.78 MHz 1.78兆赫

E5A03. What is the magnitude of the impedance of a series RLC circuit at resonance? 谐振时串联RLC电路的阻抗大小是多少？

1. High, compared to the circuit resistance 高，与电路电阻相比
2. Approximately equal to capacitive reactance 大约等于容抗
3. Approximately equal to inductive reactance 大约等于电感电抗
4. Approximately equal to circuit resistance 大致等于电路电阻

E5A04. What is the magnitude of the impedance of a parallel RLC circuit at resonance? 并联RLC电路在谐振时的阻抗大小是多少？

1. Approximately equal to circuit resistance 大致等于电路电阻
2. Approximately equal to inductive reactance 大约等于电感电抗
3. Low compared to the circuit resistance 与电路电阻相比低
4. High compared to the circuit resistance 与电路电阻相比偏高

E5A05. What is the result of increasing the Q of an impedance-matching circuit? 增加阻抗匹配电路的Q值的结果是什么？

1. Matching bandwidth is decreased 匹配带宽减少
2. Matching bandwidth is increased 匹配带宽增加
3. Losses increase 损失增加
4. Harmonics increase 谐波增加

E5A06. What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance? 谐振时并联LC电路组件内的循环电流大小是多少？

1. It is at a minimum 这是最低限度的
2. It is at a maximum 它处于最大值
3. It equals 1 divided by the quantity 2 times pi, times the square root of (inductance L multiplied by capacitance C) 它等于1除以2乘以π，乘以（电感L乘以电容C）的平方根
4. It equals 2 times pi, times the square root of (inductance L multiplied by capacitance C) 它等于π的2倍，乘以（电感L乘以电容C）的平方根

E5A07. What is the magnitude of the current at the input of a parallel RLC circuit at resonance? 谐振时并联RLC电路输入端的电流大小是多少？

1. Minimum 最低限度
2. Maximum 最大限度
3. R/L 右/左
4. L/R 左／右

E5A08. What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance? 在谐振时，通过串联谐振电路的电流和电压之间的相位关系是什么？

1. The voltage leads the current by 90 degrees 电压使电流超前90度
2. The current leads the voltage by 90 degrees 电流领先电压90度
3. The voltage and current are in phase 电压和电流同相
4. The voltage and current are 180 degrees out of phase 电压和电流相差180度

E5A09. How is the Q of an RLC parallel resonant circuit calculated? RLC并联谐振电路的Q是如何计算的？

1. Reactance of either the inductance or capacitance divided by the resistance 电感或电容的电抗除以电阻
2. Reactance of either the inductance or capacitance multiplied by the resistance 电感或电容的电抗乘以电阻
3. Resistance divided by the reactance of either the inductance or capacitance 电阻除以电感或电容的电抗
4. Reactance of the inductance multiplied by the reactance of the capacitance 电感电抗乘以电容电抗

E5A10. What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries, and C is 10 picofarads? 如果R是33欧姆，L是50微亨，C是10皮法，RLC电路的谐振频率是多少？

1. 7.12 MHz 7.12兆赫
2. 23.5 kHz 23.5千赫
3. 7.12 kHz 7.12千赫
4. 23.5 MHz 23.5兆赫

E5A11. What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150? 谐振频率为7.1MHz、Q为150的谐振电路的半功率带宽是多少？

1. 157.8 Hz 157.8赫兹
2. 315.6 Hz 315.6赫兹
3. 47.3 kHz 47.3千赫
4. 23.67 kHz 23.67千赫

E5A12. What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118? 谐振频率为3.7MHz、Q为118的谐振电路的半功率带宽是多少？

1. 436.6 kHz 436.6千赫
2. 218.3 kHz 218.3千赫
3. 31.4 kHz 31.4千赫
4. 15.7 kHz 15.7千赫

E5A13. What is an effect of increasing Q in a series resonant circuit? 在串联谐振电路中增加Q的影响是什么？

1. Fewer components are needed for the same performance 相同性能所需的组件更少
2. Parasitic effects are minimized 寄生效应最小化
3. Internal voltages increase 内部电压增加
4. Phase shift can become uncontrolled 相移可能变得不受控制

E5B01. What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage? RC电路中的电容器充电至施加电压的63.2%或放电至其初始电压的36.8%所需的时间是什么？

1. An exponential rate of one 一的指数速率
2. One time constant 一个时间常数
3. One exponential period 一个指数周期
4. A time factor of one 一的时间因子

E5B02. What letter is commonly used to represent susceptance? 电纳常用哪个字母表示？

1. G
2. X X
3. Y
4. B

E5B03. How is impedance in polar form converted to an equivalent admittance? 如何将极性形式的阻抗转换为等效导纳？

1. Take the reciprocal of the angle and change the sign of the magnitude 取角度的倒数，改变幅度的符号
2. Take the reciprocal of the magnitude and change the sign of the angle 取大小的倒数，改变角度的符号
3. Take the square root of the magnitude and add 180 degrees to the angle 取幅度的平方根，将角度加180度
4. Square the magnitude and subtract 90 degrees from the angle 将幅度平方并从角度中减去90度

E5B04. What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel? 具有两个220微法拉电容器和两个1兆欧姆电阻器的电路的时间常数是多少？

1. 55 seconds 55秒
2. 110 seconds 110秒
3. 440 seconds 440秒
4. 220 seconds 220秒

E5B05. What is the effect on the magnitude of pure reactance when it is converted to susceptance? 当纯电抗转换为电纳时，对其大小有什么影响？

1. It is unchanged 它没有变化
2. The sign is reversed 标志颠倒了
3. It is shifted by 90 degrees 它移动了90度
4. It is replaced by its reciprocal 它被它的倒数所取代

E5B06. What is susceptance? 什么是电纳？

1. The magnetic impedance of a circuit 电路的磁阻抗
2. The ratio of magnetic field to electric field 磁场与电场之比
3. The imaginary part of admittance 导纳的虚部
4. A measure of the efficiency of a transformer 变压器效率的衡量标准

E5B07. What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms? 如果XC是500欧姆，R是1千欧姆，XL是250欧姆，那么RLC串联电路两端的电压和电流之间的相位角是多少？

1. 68.2 degrees with the voltage leading the current 68.2度，电压领先电流
2. 14.0 degrees with the voltage leading the current 14.0度，电压领先电流
3. 14.0 degrees with the voltage lagging the current 14.0度，电压滞后于电流
4. 68.2 degrees with the voltage lagging the current 68.2度，电压滞后于电流

E5B08. What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 300 ohms, R is 100 ohms, and XL is 100 ohms? 如果XC为300欧姆、R为100欧姆、XL为100欧姆，则RLC串联电路两端的电压和电流之间的相位角是多少？

1. 63 degrees with the voltage lagging the current 63度，电压滞后于电流
2. 63 degrees with the voltage leading the current 63度，电压领先电流
3. 27 degrees with the voltage leading the current 27度，电压领先电流
4. 27 degrees with the voltage lagging the current 27度，电压滞后于电流

E5B09. What is the relationship between the AC current through a capacitor and the voltage across a capacitor? 通过电容器的交流电流和电容器两端的电压之间的关系是什么？

1. Voltage and current are in phase 电压和电流同相
2. Voltage and current are 180 degrees out of phase 电压和电流相差180度
3. Voltage leads current by 90 degrees 电压超前电流90度
4. Current leads voltage by 90 degrees 电流领先电压90度

E5B10. What is the relationship between the AC current through an inductor and the voltage across an inductor? 通过电感器的交流电流和电感器两端的电压之间的关系是什么？

1. Voltage leads current by 90 degrees 电压超前电流90度
2. Current leads voltage by 90 degrees 电流领先电压90度
3. Voltage and current are 180 degrees out of phase 电压和电流相差180度
4. Voltage and current are in phase 电压和电流同相

E5B11. What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 75 ohms? 如果XC为25欧姆，R为100欧姆，XL为75欧姆，则RLC串联电路两端的电压和电流之间的相位角是多少？

1. 27 degrees with the voltage lagging the current 27度，电压滞后于电流
2. 27 degrees with the voltage leading the current 27度，电压领先电流
3. 63 degrees with the voltage lagging the current 63度，电压滞后于电流
4. 63 degrees with the voltage leading the current 63度，电压领先电流

E5B12. What is admittance? 什么是准入？

1. The inverse of impedance 阻抗的倒数
2. The term for the gain of a field effect transistor 场效应晶体管增益的术语
3. The inverse of reactance 电抗的倒数
4. The term for the on-impedance of a field effect transistor 场效应晶体管导通阻抗的术语

E5C01. Which of the following represents pure capacitive reactance of 100 ohms in rectangular notation? 以下哪一项用矩形表示100欧姆的纯容抗？

1. 0 - j100 0-j100
2. 0 + j100 0+j100
3. 100 - j0 100-j0
4. 100 + j0 100+j0

E5C02. How are impedances described in polar coordinates? 如何在极坐标中描述阻抗？

1. By X and R values 按X和R值
2. By real and imaginary parts 通过实部和虚部
3. By magnitude and phase angle 按大小和相位角
4. By Y and G values 按Y和G值

E5C03. Which of the following represents a pure inductive reactance in polar coordinates? 以下哪一项表示极坐标中的纯电感电抗？

1. A positive 45 degree phase angle 正45度相位角
2. A negative 45 degree phase angle 负45度相位角
3. A positive 90 degree phase angle 正90度相位角
4. A negative 90 degree phase angle 负90度相位角

E5C04. What type of Y-axis scale is most often used for graphs of circuit frequency response? 什么类型的Y轴刻度最常用于电路频率响应图？

1. Linear 线性的
2. Scatter 分散
3. Random 随机的
4. Logarithmic 对数

E5C05. What kind of diagram is used to show the phase relationship between impedances at a given frequency? 用什么样的图来显示给定频率下阻抗之间的相位关系？

1. Venn diagram 维恩图
2. Near field diagram 近场图
3. Phasor diagram 相量图
4. Far field diagram 远场图

E5C06. What does the impedance 50 - j25 ohms represent? 阻抗50-j25欧姆代表什么？

1. 50 ohms resistance in series with 25 ohms inductive reactance 50欧姆电阻与25欧姆电感电抗串联
2. 50 ohms resistance in series with 25 ohms capacitive reactance 50欧姆电阻与25欧姆容抗串联
3. 25 ohms resistance in series with 50 ohms inductive reactance 25欧姆电阻与50欧姆电感电抗串联
4. 25 ohms resistance in series with 50 ohms capacitive reactance 25欧姆电阻与50欧姆容抗串联

E5C07. Where is the impedance of a pure resistance plotted on rectangular coordinates? 在直角坐标上绘制的纯电阻的阻抗在哪里？

1. On the vertical axis 在垂直轴上
2. On a line through the origin, slanted at 45 degrees 在穿过原点的直线上，倾斜45度
3. On a horizontal line, offset vertically above the horizontal axis 在水平线上，在水平轴上方垂直偏移
4. On the horizontal axis 在水平轴上

E5C08. What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive, and/or capacitive reactance? 通常使用什么坐标系来显示包含电阻、电感和/或容抗的电路的相位角？

1. Maidenhead grid 梅登黑德电网
2. Faraday grid 法拉第栅格
3. Elliptical coordinates 椭圆坐标
4. Polar coordinates 极坐标

E5C09. When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent? 当使用直角坐标绘制电路阻抗图时，轴代表什么？

1. The X axis represents the resistive component, and the Y axis represents the reactive component X轴表示电阻分量，Y轴表示电抗分量
2. The X axis represents the reactive component, and the Y axis represents the resistive component X轴表示电抗分量，Y轴表示电阻分量
3. The X axis represents the phase angle, and the Y axis represents the magnitude X轴表示相位角，Y轴表示幅度
4. The X axis represents the magnitude, and the Y axis represents the phase angle X轴表示幅度，Y轴表示相位角

E5C10. Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz? 图E5-1中的哪一点最能代表由400欧姆电阻器和38皮法拉电容器组成的串联电路在14 MHz下的阻抗？

1. Point 2 第2点
2. Point 4 第4点
3. Point 5 第5点
4. Point 6 第6点

E5C11. Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz? 图E5-1中的哪一点最能代表由300欧姆电阻器和18微亨电感器组成的串联电路在3.505 MHz下的阻抗？

1. Point 1 第1点
2. Point 3 第3点
3. Point 7 第7点
4. Point 8 第8点

E5C12. Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz? 图E5-1中的哪一点最能代表由300欧姆电阻器和19皮法拉电容器组成的串联电路在21.200 MHz下的阻抗？

1. Point 1 第1点
2. Point 3 第3点
3. Point 7 第7点
4. Point 8 第8点

E5D01. What is the result of conductor skin effect? 导体趋肤效应的结果是什么？

1. Resistance increases as frequency increases because RF current flows closer to the surface 电阻随着频率的增加而增加，因为RF电流流向更靠近表面
2. Resistance decreases as frequency increases because electron mobility increases 电阻随着频率的增加而减小，因为电子迁移率增加
3. Resistance increases as temperature increases because of the change in thermal coefficient 由于热系数的变化，电阻随着温度的升高而增加
4. Resistance decreases as temperature increases because of the change in thermal coefficient 由于热系数的变化，电阻随着温度的升高而减小

E5D02. Why is it important to keep lead lengths short for components used in circuits for VHF and above? 为什么保持VHF及以上电路中使用的元件的引线长度较短很重要？

1. To increase the thermal time constant 增加热时间常数
2. To minimize inductive reactance 尽量减少电感电抗
3. To maintain component lifetime 保持组件寿命
4. All these choices are correct 所有这些选择都是正确的

E5D03. What is the phase relationship between current and voltage for reactive power? 无功功率的电流和电压之间的相位关系是什么？

1. They are out of phase 它们不同步
2. They are in phase 它们处于同一阶段
3. They are 90 degrees out of phase 它们相位相差90度
4. They are 45 degrees out of phase 它们相差45度

E5D04. Why are short connections used at microwave frequencies? 为什么在微波频率下使用短连接？

1. To increase neutralizing resistance 增加中和阻力
2. To reduce phase shift along the connection 减少沿连接的相移
3. To increase compensating capacitance 增加补偿电容
4. To reduce noise figure 降低噪声系数

E5D05. What parasitic characteristic causes electrolytic capacitors to be unsuitable for use at RF? 是什么寄生特性导致电解电容器不适合用于射频？

1. Skin effect 皮肤效应
2. Shunt capacitance 并联电容
3. Inductance 电感
4. Dielectric leakage 介质泄漏

E5D06. What parasitic characteristic creates an inductor’s self-resonance? 什么寄生特性会产生电感器的自谐振？

1. Skin effect 皮肤效应
2. Dielectric loss 介电损耗
3. Coupling 联轴器
4. Inter-turn capacitance 匝间电容

E5D07. What combines to create the self-resonance of a component? 是什么结合在一起产生了组件的自共振？

1. The component’s resistance and reactance 部件的电阻和电抗
2. The component’s nominal and parasitic reactance 部件的标称电抗和寄生电抗
3. The component’s inductance and capacitance 组件的电感和电容
4. The component’s electrical length and impedance 组件的电气长度和阻抗

E5D08. What is the primary cause of loss in film capacitors at RF? 射频下薄膜电容器损耗的主要原因是什么？

1. Inductance 电感
2. Dielectric loss 介电损耗
3. Self-discharge 自放电
4. Skin effect 皮肤效应

E5D09. What happens to reactive power in ideal inductors and capacitors? 理想电感器和电容器的无功功率会发生什么变化？

1. It is dissipated as heat in the circuit 它在电路中作为热量消散
2. Energy is stored in magnetic or electric fields, but power is not dissipated 能量储存在磁场或电场中，但功率不会耗散
3. It is canceled by Coulomb forces in the capacitor and inductor 它被电容器和电感器中的库仑力抵消
4. It is dissipated in the formation of inductive and capacitive fields 它在感应场和电容场的形成中耗散

E5D10. As a conductor’s diameter increases, what is the effect on its electrical length? 随着导体直径的增加，对其电气长度有什么影响？

1. Thickness has no effect on electrical length 厚度对电气长度没有影响
2. It varies randomly 它随机变化
3. It decreases 它减少了
4. It increases 它增加了

E5D11. How much real power is consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere? 在一个由100欧姆电阻器与100欧姆电感电抗串联组成的电路中，消耗了多少实际功率？

1. 70.7 watts 70.7瓦
2. 100 watts 100瓦
3. 141.4 watts 141.4瓦
4. 200 watts 200瓦

E5D12. What is reactive power? 什么是无功功率？

1. Power consumed in circuit Q 电路Q中消耗的功率
2. Power consumed by an inductor’s wire resistance 电感器导线电阻消耗的功率
3. The power consumed in inductors and capacitors 电感器和电容器消耗的功率
4. Wattless, nonproductive power 无电、无生产力

E6A01. In what application is gallium arsenide used as a semiconductor material? 砷化镓在什么应用中被用作半导体材料？

1. In high-current rectifier circuits 在大电流整流器电路中
2. In high-power audio circuits 在高功率音频电路中
3. In microwave circuits 在微波电路中
4. In very low-frequency RF circuits 在非常低频的RF电路中

E6A02. Which of the following semiconductor materials contains excess free electrons? 以下哪种半导体材料含有过量的自由电子？

1. N-type N型
2. P-type P型
3. Bipolar 双极的
4. Insulated gate 绝缘门

E6A03. Why does a PN-junction diode not conduct current when reverse biased? 为什么PN结二极管在反向偏置时不导通电流？

1. Only P-type semiconductor material can conduct current 只有P型半导体材料才能传导电流
2. Only N-type semiconductor material can conduct current 只有N型半导体材料才能传导电流
3. Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region P型材料中的空穴和N型材料中电子被施加的电压分开，从而加宽耗尽区
4. Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator P型材料中多余的空穴与N型材料中的电子结合，将整个二极管转化为绝缘体

E6A04. What is the name given to an impurity atom that adds holes to a semiconductor crystal structure? 在半导体晶体结构中添加空穴的杂质原子的名字是什么？

1. Insulator impurity 绝缘子杂质
2. N-type impurity N型杂质
3. Acceptor impurity 受体杂质
4. Donor impurity 施主杂质

E6A05. How does DC input impedance at the gate of a field-effect transistor (FET) compare with that of a bipolar transistor? 场效应晶体管（FET）栅极的直流输入阻抗与双极晶体管的直流输入电阻相比如何？

1. They are both low impedance 它们都是低阻抗
2. An FET has lower input impedance FET的输入阻抗较低
3. An FET has higher input impedance FET具有更高的输入阻抗
4. They are both high impedance 它们都是高阻抗的

E6A06. What is the beta of a bipolar junction transistor? 双极结晶体管的β是多少？

1. The frequency at which the current gain is reduced to 0.707 电流增益降低到0.707的频率
2. The change in collector current with respect to base current 集电极电流相对于基极电流的变化
3. The breakdown voltage of the base-to-collector junction 基极-集电极结的击穿电压
4. The switching speed 切换速度

E6A07. Which of the following indicates that a silicon NPN junction transistor is biased on? 以下哪一项表明硅NPN结晶体管被偏置导通？

1. Base-to-emitter resistance of approximately 6 ohms to 7 ohms 基极到发射极的电阻约为6欧姆到7欧姆
2. Base-to-emitter resistance of approximately 0.6 ohms to 0.7 ohms 基极到发射极的电阻约为0.6欧姆到0.7欧姆
3. Base-to-emitter voltage of approximately 6 volts to 7 volts 基极至发射极电压约为6伏至7伏
4. Base-to-emitter voltage of approximately 0.6 volts to 0.7 volts 基极至发射极电压约为0.6伏至0.7伏

E6A08. What is the term for the frequency at which the grounded-base current gain of a bipolar junction transistor has decreased to 0.7 of the gain obtainable at 1 kHz? 双极结晶体管的接地基极电流增益已降至1kHz下可获得增益的0.7的频率的术语是什么？

1. Corner frequency 拐角频率
2. Alpha rejection frequency 阿尔法抑制频率
3. Beta cutoff frequency 贝塔截止频率
4. Alpha cutoff frequency Alpha截止频率

E6A09. What is a depletion-mode field-effect transistor (FET)? 什么是耗尽型场效应晶体管（FET）？

1. An FET that exhibits a current flow between source and drain when no gate voltage is applied 当没有施加栅极电压时，在源极和漏极之间呈现电流流动的FET
2. An FET that has no current flow between source and drain when no gate voltage is applied 当没有施加栅极电压时，源极和漏极之间没有电流流动的FET
3. An FET that exhibits very high electron mobility due to a lack of holes in the N-type material 由于N型材料中缺乏空穴而表现出非常高的电子迁移率的FET
4. An FET for which holes are the majority carriers 空穴占多数载流子的FET

E6A10. In Figure E6-1, which is the schematic symbol for an N-channel dual-gate MOSFET? 在图E6-1中，哪个是N沟道双栅极MOSFET的示意符号？

1. 2 2
2. 4 4
3. 5 5
4. 6 6

E6A11. In Figure E6-1, which is the schematic symbol for a P-channel junction FET? 在图E6-1中，哪个是P沟道结FET的示意符号？

1. 1 1
2. 2 2
3. 3 3
4. 6 6

E6A12. What is the purpose of connecting Zener diodes between a MOSFET gate and its source or drain? 在MOSFET栅极和源极或漏极之间连接齐纳二极管的目的是什么？

1. To provide a voltage reference for the correct amount of reverse-bias gate voltage 为正确量的反向偏置栅极电压提供电压参考
2. To protect the substrate from excessive voltages 保护基板免受过电压的影响
3. To keep the gate voltage within specifications and prevent the device from overheating 将栅极电压保持在规格范围内并防止设备过热
4. To protect the gate from static damage 保护闸门免受静态损坏

E6B01. What is the most useful characteristic of a Zener diode? 齐纳二极管最有用的特性是什么？

1. A constant current drop under conditions of varying voltage 电压变化条件下的恒定电流降
2. A constant voltage drop under conditions of varying current 变化电流条件下的恒定电压降
3. A negative resistance region 负电阻区域
4. An internal capacitance that varies with the applied voltage 随施加电压变化的内部电容

E6B02. Which characteristic of a Schottky diode makes it a better choice than a silicon junction diode for use as a power supply rectifier? 肖特基二极管的哪个特性使其成为比硅结二极管更好的电源整流器选择？

1. Much higher reverse voltage breakdown 更高的反向电压击穿
2. More constant reverse avalanche voltage 更恒定的反向雪崩电压
3. Longer carrier retention time 更长的载体保留时间
4. Lower forward voltage drop 降低正向电压降

E6B03. What property of an LED's semiconductor material determines its forward voltage drop? LED的半导体材料的什么特性决定了其正向电压降？

1. Intrinsic resistance 固有电阻
2. Band gap 带隙
3. Junction capacitance 结电容
4. Junction depth 接合深度

E6B04. What type of semiconductor device is designed for use as a voltage-controlled capacitor? 什么类型的半导体器件被设计用作电压控制电容器？

1. Varactor diode 变容二极管
2. Tunnel diode 隧道二极管
3. Silicon-controlled rectifier 可控硅整流器
4. Zener diode 齐纳二极管

E6B05. What characteristic of a PIN diode makes it useful as an RF switch? PIN二极管的什么特性使其可用作RF开关？

1. Extremely high reverse breakdown voltage 极高的反向击穿电压
2. Ability to dissipate large amounts of power 消耗大量电力的能力
3. Reverse bias controls its forward voltage drop 反向偏置控制其正向电压降
4. Low junction capacitance 低结电容

E6B06. Which of the following is a common use of a Schottky diode? 以下哪项是肖特基二极管的常用项？

1. In oscillator circuits as the negative resistance element 在振荡器电路中作为负电阻元件
2. As a variable capacitance in an automatic frequency control circuit 作为自动频率控制电路中的可变电容
3. In power supplies as a constant voltage reference 在电源中作为恒压参考
4. As a VHF/UHF mixer or detector 作为VHF/UHF混频器或检波器

E6B07. What causes a junction diode to fail from excessive current? 是什么导致结型二极管因电流过大而失效？

1. Excessive inverse voltage 反向电压过高
2. Excessive junction temperature 结温过高
3. Insufficient forward voltage 正向电压不足
4. Charge carrier depletion 电荷载流子耗尽

E6B08. Which of the following is a Schottky barrier diode? 以下哪一项是肖特基势垒二极管？

1. Metal-semiconductor junction 金属半导体结
2. Electrolytic rectifier 电解整流器
3. PIN junction PIN接线
4. Thermionic emission diode 热离子发射二极管

E6B09. What is a common use for point-contact diodes? 点接触二极管的常见用途是什么？

1. As a constant current source 作为恒流源
2. As a constant voltage source 作为恒压源
3. As an RF detector 作为射频探测器
4. As a high-voltage rectifier 作为高压整流器

E6B10. In Figure E6-2, which is the schematic symbol for a Schottky diode? 在图E6-2中，肖特基二极管的示意符号是什么？

1. 1 1
2. 6 6
3. 2 2
4. 3 3

E6B11. What is used to control the attenuation of RF signals by a PIN diode? PIN二极管用来控制射频信号的衰减的是什么？

1. Forward DC bias current 正向直流偏置电流
2. A variable RF reference voltage 可变射频参考电压
3. Reverse voltage larger than the RF signal 反向电压大于射频信号
4. Capacitance of an RF coupling capacitor 射频耦合电容器的电容

E6C01. What is the function of hysteresis in a comparator? 比较器中磁滞的作用是什么？

1. To prevent input noise from causing unstable output signals 防止输入噪声导致输出信号不稳定
2. To allow the comparator to be used with AC input signals 允许比较器与交流输入信号一起使用
3. To cause the output to continually change states 使输出不断改变状态
4. To increase the sensitivity 增加灵敏度

E6C02. What happens when the level of a comparator’s input signal crosses the threshold voltage? 当比较器的输入信号的电平超过阈值电压时会发生什么？

1. The IC input can be damaged IC输入可能损坏
2. The comparator changes its output state 比较器改变其输出状态
3. The reference level appears at the output 参考电平出现在输出端
4. The feedback loop becomes unstable 反馈回路变得不稳定

E6C03. What is tri-state logic? 什么是三态逻辑？

1. Logic devices with 0, 1, and high-impedance output states 具有0、1和高阻抗输出状态的逻辑器件
2. Logic devices that utilize ternary math 利用三元数学的逻辑器件
3. Logic with three output impedances which can be selected to better match the load impedance 具有三个输出阻抗的逻辑，可进行选择以更好地匹配负载阻抗
4. A counter with eight states 一个有八种状态的计数器

E6C04. Which of the following is an advantage of BiCMOS logic? 以下哪项是BiCMOS逻辑的优势？

1. Its simplicity results in much less expensive devices than standard CMOS 它的简单性使得器件比标准CMOS便宜得多
2. It is immune to electrostatic damage 它不受静电损伤
3. It has the high input impedance of CMOS and the low output impedance of bipolar transistors 它具有CMOS的高输入阻抗和双极晶体管的低输出阻抗
4. All these choices are correct 所有这些选择都是正确的

E6C05. Which of the following digital logic families has the lowest power consumption? 以下哪个数字逻辑系列的功耗最低？

1. Schottky TTL 肖特基TTL
2. ECL
3. NMOS
4. CMOS 互补金属氧化物半导体

E6C06. Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply? 为什么CMOS数字集成电路对输入信号或电源上的噪声具有高抗扰度？

1. Large bypass capacitance is inherent 大的旁路电容是固有的
2. The input switching threshold is about twice the power supply voltage 输入开关阈值大约是电源电压的两倍
3. The input switching threshold is about half the power supply voltage 输入开关阈值大约是电源电压的一半
4. Bandwidth is very limited 带宽非常有限

E6C07. What best describes a pull-up or pull-down resistor? 什么最能描述上拉电阻或下拉电阻？

1. A resistor in a keying circuit used to reduce key clicks 键控电路中用于减少按键点击的电阻器
2. A resistor connected to the positive or negative supply used to establish a voltage when an input or output is an open circuit 连接到正极或负极电源的电阻器，用于在输入或输出开路时建立电压
3. A resistor that ensures that an oscillator frequency does not drift 确保振荡器频率不漂移的电阻器
4. A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage 连接到运算放大器输出的电阻器，用于防止信号超过电源电压

E6C08. In Figure E6-3, which is the schematic symbol for a NAND gate? 在图E6-3中，哪一个是NAND门的示意符号？

1. 1 1
2. 2 2
3. 3 3
4. 4 4

E6C09. What is used to design the configuration of a field-programmable gate array (FPGA)? 如何设计现场可编程门阵列（FPGA）的配置？

1. Karnaugh maps 卡诺图
2. Hardware description language (HDL) 硬件描述语言（HDL）
3. An auto-router 自动路由器
4. Machine and assembly language 机器和汇编语言

E6C10. In Figure E6-3, which is the schematic symbol for a NOR gate? 在图E6-3中，NOR门的示意符号是什么？

1. 1 1
2. 2 2
3. 3 3
4. 4 4

E6C11. In Figure E6-3, which is the schematic symbol for the NOT operation (inversion)? 在图E6-3中，NOT操作（反转）的示意符号是哪一个？

1. 2 2
2. 4 4
3. 5 5
4. 6 6

E6D01. What is piezoelectricity? 什么是压电？

1. The ability of materials to generate electromagnetic waves of a certain frequency when voltage is applied 当施加电压时，材料产生特定频率电磁波的能力
2. A characteristic of materials that have an index of refraction which depends on the polarization of the electromagnetic wave passing through it 折射率取决于穿过材料的电磁波的偏振的材料的一种特性
3. A characteristic of materials that generate a voltage when stressed and that flex when a voltage is applied 材料的一种特性，当受到应力时会产生电压，当施加电压时会弯曲
4. The ability of materials to generate voltage when an electromagnetic wave of a certain frequency is applied 当施加特定频率的电磁波时，材料产生电压的能力

E6D02. What is the equivalent circuit of a quartz crystal? 石英晶体的等效电路是什么？

1. Series RLC in parallel with a shunt C representing electrode and stray capacitance 串联RLC与代表电极和杂散电容的分流器C并联
2. Parallel RLC, where C is the parallel combination of resonance capacitance of the crystal and electrode and stray capacitance 并联RLC，其中C是晶体和电极的谐振电容与杂散电容的并联组合
3. Series RLC, where C is the parallel combination of resonance capacitance of the crystal and electrode and stray capacitance RLC系列，其中C是晶体和电极的谐振电容与杂散电容的并联组合
4. Parallel RLC, where C is the series combination of resonance capacitance of the crystal and electrode and stray capacitance 并联RLC，其中C是晶体和电极的谐振电容与杂散电容的串联组合

E6D03. Which of the following is an aspect of the piezoelectric effect? 以下哪一项是压电效应的一个方面？

1. Mechanical deformation of material due to the application of a voltage 施加电压导致材料的机械变形
2. Mechanical deformation of material due to the application of a magnetic field 磁场作用下材料的机械变形
3. Generation of electrical energy in the presence of light 在光的存在下产生电能
4. Increased conductivity in the presence of light 在光的存在下提高导电性

E6D04. Why are cores of inductors and transformers sometimes constructed of thin layers? 为什么电感器和变压器的核心有时是由薄层构成的？

1. To simplify assembly during manufacturing 简化制造过程中的装配
2. To reduce power loss from eddy currents in the core 减少堆芯涡流造成的功率损失
3. To increase the cutoff frequency by reducing capacitance 通过减少电容来增加截止频率
4. To save cost by reducing the amount of magnetic material 通过减少磁性材料的数量来节省成本

E6D05. How do ferrite and powdered iron compare for use in an inductor core? 铁氧体和铁粉在电感器磁芯中的使用比较如何？

1. Ferrite cores generally have lower initial permeability 铁氧体磁芯通常具有较低的初始磁导率
2. Ferrite cores generally have better temperature stability 铁氧体磁芯通常具有更好的温度稳定性
3. Ferrite cores generally require fewer turns to produce a given inductance value 铁氧体磁芯通常需要较少的匝数才能产生给定的电感值
4. Ferrite cores are easier to use with surface-mount technology 表面贴装技术使铁氧体磁芯更易于使用

E6D06. What core material property determines the inductance of an inductor? 什么样的核心材料特性决定了电感器的电感？

1. Permittivity 介电常数
2. Resistance 反对
3. Reactivity 反应性
4. Permeability 渗透

E6D07. What is the current that flows in the primary winding of a transformer when there is no load on the secondary winding? 当次级绕组上没有负载时，变压器初级绕组中的电流是多少？

1. Stabilizing current 稳定电流
2. Direct current 直流电
3. Excitation current 励磁电流
4. Magnetizing current 磁化电流

E6D08. Which of the following materials has the highest temperature stability of its magnetic characteristics? 以下哪种材料的磁特性具有最高的温度稳定性？

1. Brass 黄铜
2. Powdered iron 粉末状铁
3. Ferrite 铁氧体
4. Aluminum 铝

E6D09. What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier? 晶体管高频放大器的输入和输出端通常使用哪些设备作为VHF和UHF寄生抑制器？

1. Electrolytic capacitors 电解电容器
2. Butterworth filters 巴特沃斯过滤器
3. Ferrite beads 铁氧体磁珠
4. Steel-core toroids 钢芯环面

E6D10. What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor? 在电感器中使用环形磁芯而不是螺线管磁芯的主要优点是什么？

1. Toroidal cores confine most of the magnetic field within the core material 环形磁芯将大部分磁场限制在磁芯材料内
2. Toroidal cores make it easier to couple the magnetic energy into other components 环形磁芯更容易将磁能耦合到其他部件中
3. Toroidal cores exhibit greater hysteresis 环形磁芯表现出更大的磁滞
4. Toroidal cores have lower Q characteristics 环形铁芯具有较低的Q特性

E6D11. Which type of core material decreases inductance when inserted into a coil? 哪种类型的磁芯材料在插入线圈时会降低电感？

1. Ceramic 陶瓷
2. Brass 黄铜
3. Ferrite 铁氧体
4. Aluminum 铝

E6D12. What causes inductor saturation? 电感器饱和的原因是什么？

1. Operation at too high a frequency 操作频率过高
2. Selecting a core with low permeability 选择低渗透率岩心
3. Operation at excessive magnetic flux 磁通量过大时的操作
4. Selecting a core with excessive permittivity 选择介电常数过高的磁芯

E6E01. Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies? 为什么砷化镓（GaAs）对工作在UHF和更高频率下的半导体器件有用？

1. Higher noise figures 较高的噪声系数
2. Higher electron mobility 更高的电子迁移率
3. Lower junction voltage drop 较低的结电压降
4. Lower transconductance 更低的跨导

E6E02. Which of the following device packages is a through-hole type? 以下哪种设备封装是通孔型的？

1. DIP 倾斜
2. PLCC 塑料芯片载体
3. BGA 球栅阵列
4. SOT 单边订单追踪（证券交易术语）

E6E03. Which of the following materials supports the highest frequency of operation when used in MMICs? 以下哪种材料在MMIC中使用时支持最高工作频率？

1. Silicon 硅
2. Silicon nitride 氮化硅
3. Silicon dioxide 二氧化硅
4. Gallium nitride 氮化镓

E6E04. Which is the most common input and output impedance of MMICs? MMIC最常见的输入和输出阻抗是什么？

1. 50 ohms 50欧姆
2. 300 ohms 300欧姆
3. 450 ohms 450欧姆
4. 75 ohms 75欧姆

E6E05. Which of the following noise figure values is typical of a low-noise UHF preamplifier? 以下哪一个噪声值是低噪声UHF前置放大器的典型值？

1. 0.5 dB 0.5分贝
2. -10 dB -10分贝
3. 44 dBm
4. -20 dBm

E6E06. What characteristics of MMICs make them a popular choice for VHF through microwave circuits? MMIC的哪些特性使其成为VHF直通微波电路的热门选择？

1. The ability to retrieve information from a single signal, even in the presence of other strong signals 即使在存在其他强信号的情况下，也能从单个信号中检索信息
2. Extremely high Q factor and high stability over a wide temperature range 极高的Q因子和在宽温度范围内的高稳定性
3. Nearly infinite gain, very high input impedance, and very low output impedance 几乎无限增益，非常高的输入阻抗和非常低的输出阻抗
4. Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range 受控增益、低噪声系数以及在指定频率范围内的恒定输入和输出阻抗

E6E07. What type of transmission line is often used for connections to MMICs? 通常使用哪种类型的传输线连接MMIC？

1. Miniature coax 微型同轴电缆
2. Circular waveguide 圆形波导管
3. Parallel wire 平行导线
4. Microstrip 微带

E6E08. How is power supplied to the most common type of MMIC? 最常见的MMIC是如何供电的？

1. Through a capacitor and RF choke connected to the amplifier input lead 通过连接到放大器输入引线的电容器和RF扼流圈
2. MMICs require no operating bias MMIC不需要操作偏置
3. Through a resistor and/or RF choke connected to the amplifier output lead 通过连接到放大器输出引线的电阻器和/或RF扼流圈
4. Directly to the bias voltage (Vcc) lead 直接连接到偏置电压（Vcc）引线

E6E09. Which of the following component package types have the least parasitic effects at frequencies above the HF range? 以下哪种组件封装类型在HF范围以上的频率下具有最小的寄生效应？

1. TO-220 至220
2. Axial lead 轴向引线
3. Radial lead 径向引线
4. Surface mount 表面安装

E6E10. What advantage does surface-mount technology offer at RF compared to using through-hole components? 与使用通孔组件相比，表面安装技术在射频方面有什么优势？

1. Smaller circuit area 较小的电路面积
2. Shorter circuit board traces 电路板迹线较短
3. Components have less parasitic inductance and capacitance 元件具有较小的寄生电感和电容
4. All these choices are correct 所有这些选择都是正确的

E6E11. What is a characteristic of DIP packaging used for integrated circuits? 用于集成电路的DIP封装的特性是什么？

1. Extremely low stray capacitance (dielectrically isolated package) 极低杂散电容（介质隔离封装）
2. Extremely high resistance between pins (doubly insulated package) 引脚间电阻极高（双绝缘封装）
3. Two chips in each package (dual in package) 每个封装中有两个芯片（双入封装）
4. Two rows of connecting pins on opposite sides of package (dual in-line package) 封装相对两侧的两排连接引脚（双列直插封装）

E6E12. Why are DIP through-hole package ICs not typically used at UHF and higher frequencies? 为什么DIP通孔封装IC通常不用于UHF和更高频率？

1. Excessive dielectric loss 介电损耗过大
2. Epoxy coating is conductive above 300 MHz 环氧涂层在300 MHz以上具有导电性
3. Excessive lead length 导线长度过长
4. Unsuitable for combining analog and digital signals 不适合组合模拟和数字信号

E6F01. What absorbs the energy from light falling on a photovoltaic cell? 是什么吸收落在光伏电池上的光的能量？

1. Protons 质子
2. Photons 光子
3. Electrons 电子
4. Holes 洞

E6F02. What happens to photoconductive material when light shines on it? 当光照射到光导材料上时，它会发生什么？

1. Resistance decreases 电阻减小
2. Resistance increases 阻力增加
3. Reflectivity increases 反射率增加
4. Reflectivity decreases 反射率降低

E6F03. What is the most common configuration of an optoisolator or optocoupler? 光隔离器或光耦合器最常见的配置是什么？

1. A lens and a photomultiplier 一个透镜和一个光电倍增管
2. A frequency-modulated helium-neon laser 调频氦氖激光器
3. An amplitude-modulated helium-neon laser 振幅调制氦氖激光器
4. An LED and a phototransistor 一个LED和一个光电晶体管

E6F04. What is the photovoltaic effect? 光伏效应是什么？

1. The conversion of voltage to current when exposed to light 曝光时电压到电流的转换
2. The conversion of light to electrical energy 光到电能的转换
3. The effect that causes a photodiode to emit light when a voltage is applied 施加电压时使光电二极管发光的效果
4. The effect that causes a phototransistor’s beta to decrease when exposed to light 当暴露在光下时，导致光电晶体管的β降低的效应

E6F05. Which of the following describes an optical shaft encoder? 以下哪项描述了光学轴编码器？

1. A device that detects rotation by interrupting a light source with a patterned wheel 一种通过用带图案的轮子中断光源来检测旋转的设备
2. A device that measures the strength of a beam of light using analog-to-digital conversion 一种使用模数转换测量光束强度的设备
3. An optical computing device in which light is coupled between devices by fiber optics 一种光学计算设备，其中光通过光纤在设备之间耦合
4. A device for generating RTTY signals by means of a rotating light source 一种通过旋转光源产生RTTY信号的装置

E6F06. Which of these materials is most commonly used to create photoconductive devices? 以下哪种材料最常用于制作光电导器件？

1. Polyphenol acetate 多酚乙酸酯
2. Argon 氩气
3. Crystalline semiconductor 结晶半导体
4. All these choices are correct 所有这些选择都是正确的

E6F07. What is a solid-state relay? 什么是固态继电器？

1. A relay that uses transistors to drive the relay coil 一种使用晶体管驱动继电器线圈的继电器
2. A device that uses semiconductors to implement the functions of an electromechanical relay 一种使用半导体实现机电继电器功能的设备
3. A mechanical relay that latches in the on or off state each time it is pulsed 一种机械继电器，每次脉冲时都会锁定在打开或关闭状态
4. A semiconductor switch that uses a monostable multivibrator circuit 一种使用单稳态多谐振荡器电路的半导体开关

E6F08. Why are optoisolators often used in conjunction with solid-state circuits that control 120 VAC circuits? 为什么光隔离器经常与控制120 VAC电路的固态电路结合使用？

1. Optoisolators provide a low-impedance link between a control circuit and a power circuit 光隔离器在控制电路和电源电路之间提供低阻抗连接
2. Optoisolators provide impedance matching between the control circuit and power circuit 光隔离器提供控制电路和电源电路之间的阻抗匹配
3. Optoisolators provide an electrical isolation between a control circuit and the circuit being switched 光隔离器提供控制电路和被切换电路之间的电隔离
4. Optoisolators eliminate the effects of reflected light in the control circuit 光隔离器消除了控制电路中反射光的影响

E6F09. What is the efficiency of a photovoltaic cell? 光伏电池的效率是多少？

1. The output RF power divided by the input DC power 输出射频功率除以输入直流功率
2. The output in lumens divided by the input power in watts 以流明为单位的输出除以以瓦特为单位的输入功率
3. The open-circuit voltage divided by the short-circuit current under full illumination 开路电压除以全照明下的短路电流
4. The relative fraction of light that is converted to current 转换为电流的光的相对分数

E6F10. What is the most common material used in power-generating photovoltaic cells? 发电光伏电池中最常见的材料是什么？

1. Selenium 硒
2. Silicon 硅
3. Cadmium sulfide 硫化镉
4. Indium arsenide 砷化铟

E6F11. What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell? 全照明硅光伏电池产生的近似开路电压是多少？

1. 0.5 volts 0.5伏
2. 0.7 volts 0.7伏
3. 1.1 volts 1.1伏
4. 1.5 volts 1.5伏

E7A01. Which circuit is bistable? 哪个电路是双稳态的？

1. An AND gate AND门
2. An OR gate OR门
3. A flip-flop 触发器
4. A bipolar amplifier 双极放大器

E7A02. What is the function of a decade counter? 十年计数器的功能是什么？

1. It produces one output pulse for every 10 input pulses 它每10个输入脉冲产生一个输出脉冲
2. It decodes a decimal number for display on a seven-segment LED display 它对十进制数字进行解码，以便在七段LED显示屏上显示
3. It produces 10 output pulses for every input pulse 它为每个输入脉冲产生10个输出脉冲
4. It decodes a binary number for display on a seven-segment LED display 它对二进制数字进行解码，以便在七段LED显示器上显示

E7A03. Which of the following can divide the frequency of a pulse train by 2? 以下哪项可以将脉冲串的频率除以2？

1. An XOR gate XOR门
2. A flip-flop 触发器
3. An OR gate OR门
4. A multiplexer 多路复用器

E7A04. How many flip-flops are required to divide a signal frequency by 16? 将信号频率除以16需要多少个触发器？

1. 4 4
2. 6 6
3. 8 8
4. 16 16

E7A05. Which of the following circuits continuously alternates between two states without an external clock signal? 以下哪种电路在没有外部时钟信号的情况下在两种状态之间连续交替？

1. Monostable multivibrator 单稳态多谐振荡器
2. J-K flip-flop J-K触发器
3. T flip-flop T触发器
4. Astable multivibrator 不稳定多谐振荡器

E7A06. What is a characteristic of a monostable multivibrator? 单稳态多谐振荡器的特性是什么？

1. It switches temporarily to an alternate state for a set time 它在设定的时间内临时切换到备用状态
2. It produces a continuous square wave 它会产生连续的方波
3. It stores one bit of data 它存储一位数据
4. It maintains a constant output voltage, regardless of variations in the input voltage 无论输入电压如何变化，它都能保持恒定的输出电压

E7A07. What logical operation does a NAND gate perform? NAND门执行什么逻辑操作？

1. It produces a 0 at its output only if all inputs are 0 只有当所有输入都为0时，它才会在输出端产生0
2. It produces a 1 at its output only if all inputs are 1 只有当所有输入都为1时，它才会在输出端产生1
3. It produces a 0 at its output if some but not all inputs are 1 如果部分但不是全部输入为1，则在其输出处产生0
4. It produces a 0 at its output only if all inputs are 1 只有当所有输入都为1时，它才会在输出端产生0

E7A08. What logical operation does an OR gate perform? 或门执行什么逻辑运算？

1. It produces a 1 at its output if any input is 1 如果任何输入为1，则在输出端产生1
2. It produces a 0 at its output if all inputs are 1 如果所有输入都为1，则在输出端产生0
3. It produces a 0 at its output if some but not all inputs are 1 如果部分但不是全部输入为1，则在其输出处产生0
4. It produces a 1 at its output if all inputs are 0 如果所有输入都为0，则在输出端产生1

E7A09. What logical operation is performed by a two-input exclusive NOR gate? 双输入异或非门执行什么逻辑运算？

1. It produces a 0 at its output only if all inputs are 0 只有当所有输入都为0时，它才会在输出端产生0
2. It produces a 1 at its output only if all inputs are 1 只有当所有输入都为1时，它才会在输出端产生1
3. It produces a 0 at its output if one and only one of its inputs is 1 如果它的一个且仅一个输入为1，则它在输出端产生0
4. It produces a 1 at its output if one and only one input is 1 如果一个且只有一个输入为1，则在输出端产生1

E7A10. What is a truth table? 什么是真值表？

1. A list of inputs and corresponding outputs for an op-amp 运算放大器的输入和相应输出列表
2. A list of inputs and corresponding outputs for a digital device 数字设备的输入和相应输出列表
3. A diagram showing logic states when the digital gate output is true 显示数字门输出为真时的逻辑状态的图表
4. A table of logic symbols that indicate the logic states of an op-amp 指示运算放大器逻辑状态的逻辑符号表

E7A11. What does “positive logic” mean in reference to logic devices? 关于逻辑器件，“正逻辑”是什么意思？

1. The logic devices have high noise immunity 逻辑器件具有高抗噪性
2. High voltage represents a 1, low voltage a 0 高电压表示1，低电压表示0
3. The logic circuit is in the “true” condition 逻辑电路处于“真实”状态
4. 1s and 0s are defined as different positive voltage levels 1和0被定义为不同的正电压电平

E7B01. For what portion of the signal cycle does each active element in a push-pull, Class AB amplifier conduct? 推挽式AB类放大器中的每个有源元件在信号周期的哪个部分导通？

1. More than 180 degrees but less than 360 degrees 大于180度但小于360度
2. Exactly 180 degrees 正好180度
3. The entire cycle 整个周期
4. Less than 180 degrees 小于180度

E7B02. What is a Class D amplifier? 什么是D类放大器？

1. An amplifier that uses switching technology to achieve high efficiency 一种使用开关技术实现高效率的放大器
2. A low power amplifier that uses a differential amplifier for improved linearity 一种使用差分放大器以提高线性度的低功率放大器
3. An amplifier that uses drift-mode FETs for high efficiency 一种使用漂移模式FET实现高效率的放大器
4. An amplifier biased to be relatively free from distortion 一种被偏置以相对不失真的放大器

E7B03. What circuit is required at the output of an RF switching amplifier? 射频开关放大器的输出端需要什么电路？

1. A filter to remove harmonic content 去除谐波含量的滤波器
2. A high-pass filter to compensate for low gain at low frequencies 一种高通滤波器，用于补偿低频下的低增益
3. A matched load resistor to prevent damage by switching transients 一个匹配的负载电阻器，以防止开关瞬态造成的损坏
4. A temperature compensating load resistor to improve linearity 一种用于提高线性度的温度补偿负载电阻器

E7B04. What is the operating point of a Class A common emitter amplifier? a类共射极放大器的工作点是什么？

1. Approximately halfway between saturation and cutoff 大约介于饱和和截止之间
2. Approximately halfway between the emitter voltage and the base voltage 大约在发射极电压和基极电压之间的一半
3. At a point where the bias resistor equals the load resistor 在偏置电阻器等于负载电阻器的点处
4. At a point where the load line intersects the zero bias current curve 在负载线与零偏置电流曲线相交的点处

E7B05. What can be done to prevent unwanted oscillations in an RF power amplifier? 如何防止射频功率放大器出现不必要的振荡？

1. Tune the stage for minimum loading 将舞台调到最小负载
2. Tune both the input and output for maximum power 调整输入和输出以获得最大功率
3. Install parasitic suppressors and/or neutralize the stage 安装寄生抑制器和/或中和级
4. Use a phase inverter in the output filter 在输出滤波器中使用倒相器

E7B06. What is a characteristic of a grounded-grid amplifier? 接地栅极放大器的特性是什么？

1. High power gain 高功率增益
2. Low input impedance 低输入阻抗
3. High electrostatic damage protection 高静电损伤保护
4. Low bandwidth 低带宽

E7B07. Which of the following is the likely result of using a Class C amplifier to amplify a single-sideband phone signal? 以下哪项可能是使用C类放大器放大单边带电话信号的结果？

1. Reduced intermodulation products 减少互调产物
2. Increased overall intelligibility 提高整体清晰度
3. Reduced third-order intermodulation 降低了三阶互调
4. Signal distortion and excessive bandwidth 信号失真和带宽过大

E7B08. Why are switching amplifiers more efficient than linear amplifiers? 为什么开关放大器比线性放大器更有效率？

1. Switching amplifiers operate at higher voltages 开关放大器在较高电压下工作
2. The switching device is at saturation or cutoff most of the time 开关设备大部分时间处于饱和或截止状态
3. Linear amplifiers have high gain resulting in higher harmonic content 线性放大器具有高增益，从而产生更高的谐波含量
4. Switching amplifiers use push-pull circuits 开关放大器使用推挽电路

E7B09. What is characteristic of an emitter follower (or common collector) amplifier? 射极跟随器（或共集电极）放大器的特性是什么？

1. Low input impedance and phase inversion from input to output 低输入阻抗和从输入到输出的相位反转
2. Differential inputs and single output 差分输入和单输出
3. Acts as an OR circuit if one input is grounded 如果一个输入接地，则充当OR电路
4. Input and output signals in-phase 输入和输出信号同相

E7B10. In Figure E7-1, what is the purpose of R1 and R2? 在图E7-1中，R1和R2的用途是什么？

1. Load resistors 负载电阻器
2. Voltage divider bias 分压器偏置
3. Self bias 自我偏见
4. Feedback 反馈

E7B11. In Figure E7-1, what is the purpose of R3? 在图E7-1中，R3的用途是什么？

1. Fixed bias 固定偏置
2. Emitter bypass 发射器旁路
3. Output load resistor 输出负载电阻器
4. Self bias 自我偏见

E7B12. What type of amplifier circuit is shown in Figure E7-1? 图E7-1中显示了哪种类型的放大器电路？

1. Common base 公共基础
2. Common collector 公用收集器
3. Common emitter 公共发射器
4. Emitter follower 发射器跟随器

E7C01. How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network’s input and output? 低通滤波器Pi网络的电容器和电感器是如何布置在网络的输入和输出之间的？

1. Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground 两个电感器串联在输入和输出之间，一个电容器连接在两个电阻器和地之间
2. Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground 两个电容器串联在输入和输出之间，一个电感器连接在两个电容和地之间
3. An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output 一个电感器连接在输入和地之间，另一个电阻器连接在输出和地之间
4. A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between the input and output 一个电容器连接在输入和地之间，另一个电容连接在输出和地之间以及一个电感器连接在该输入和输出之间

E7C02. What is the frequency response of a T-network with series capacitors and a shunt inductor? 具有串联电容器和并联电感器的T型网络的频率响应是多少？

1. Low-pass 低通
2. High-pass 高通
3. Band-pass 带通
4. Notch 缺口

E7C03. What is the purpose of adding an inductor to a Pi-network to create a Pi-L-network? 在Pi网络中添加电感器以创建Pi-L网络的目的是什么？

1. Greater harmonic suppression 更大的谐波抑制
2. Higher efficiency 更高的效率
3. To eliminate one capacitor 消除一个电容器
4. Greater transformation range 更大的转换范围

E7C04. How does an impedance-matching circuit transform a complex impedance to a resistive impedance? 阻抗匹配电路如何将复阻抗转换为电阻阻抗？

1. It introduces negative resistance to cancel the resistive part of impedance 它引入负电阻来抵消阻抗的电阻部分
2. It introduces transconductance to cancel the reactive part of impedance 它引入跨导来抵消阻抗的电抗部分
3. It cancels the reactive part of the impedance and changes the resistive part to the desired value 它取消了阻抗的电抗部分，并将电阻部分更改为所需值
4. Reactive currents are dissipated in matched resistances 无功电流在匹配的电阻中耗散

E7C05. Which filter type has ripple in the passband and a sharp cutoff? 哪种滤波器类型在通带中具有波纹和尖锐的截止？

1. A Butterworth filter 巴特沃斯滤波器
2. An active LC filter 有源LC滤波器
3. A passive op-amp filter 无源运算放大器滤波器
4. A Chebyshev filter 切比雪夫滤波器

E7C06. What are the characteristics of an elliptical filter? 椭圆滤波器的特性是什么？

1. Gradual passband rolloff with minimal stop-band ripple 具有最小阻带波纹的渐进通带滚降
2. Extremely flat response over its pass band with gradually rounded stop-band corners 通带上的响应非常平坦，阻带角逐渐变圆
3. Extremely sharp cutoff with one or more notches in the stop band 在阻带上有一个或多个缺口的非常锋利的切口
4. Gradual passband rolloff with extreme stop-band ripple 带极端阻带波纹的渐变通带滚降

E7C07. Which describes a Pi-L network? 哪个描述了Pi-L网络？

1. A Phase Inverter Load network A相逆变器负载网络
2. A Pi-network with an additional output series inductor 具有附加输出串联电感器的Pi网络
3. A network with only three discrete parts 只有三个分立部分的网络
4. A matching network in which all components are isolated from ground 所有组件与地面隔离的匹配网络

E7C08. Which of the following is most frequently used as a band-pass or notch filter in VHF and UHF transceivers? 以下哪一项最常用作VHF和UHF收发器中的带通或陷波滤波器？

1. A Sallen-Key filter Sallen-Key过滤器
2. A helical filter 螺旋过滤器
3. A swinging choke filter 摆动式阻风门过滤器
4. A finite impulse response filter 一种有限脉冲响应滤波器

E7C09. What is a crystal lattice filter? 什么是晶格滤波器？

1. A power supply filter made with interlaced quartz crystals 一种由交错石英晶体制成的电源滤波器
2. An audio filter made with four quartz crystals that resonate at 1 kHz intervals 由四个石英晶体制成的音频滤波器，以1 kHz的间隔谐振
3. A filter using lattice-shaped quartz crystals for high-Q performance 一种使用晶格状石英晶体实现高Q性能的滤波器
4. A filter for low-level signals made using quartz crystals 一种使用石英晶体制作的低电平信号滤波器

E7C10. Which of the following filters is used in a 2-meter band repeater duplexer? 以下哪种滤波器用于2米波段的中继器双工器？

1. A crystal filter 晶体滤波器
2. A cavity filter 空腔过滤器
3. A DSP filter DSP滤波器
4. An L-C filter L-C滤波器

E7C11. Which of the following measures a filter’s ability to reject signals in adjacent channels? 以下哪项测量滤波器抑制相邻信道中信号的能力？

1. Passband ripple 通带波纹
2. Phase response 相位响应
3. Shape factor 形状系数
4. Noise factor 噪声系数

E7D01. How does a linear electronic voltage regulator work? 线性电子电压调节器是如何工作的？

1. It has a ramp voltage as its output 它的输出是斜坡电压
2. It eliminates the need for a pass transistor 它消除了对传输晶体管的需要
3. The control element duty cycle is proportional to the line or load conditions 控制元件占空比与线路或负载条件成比例
4. The conduction of a control element is varied to maintain a constant output voltage 改变控制元件的导通以保持恒定的输出电压

E7D02. How does a switchmode voltage regulator work? 开关模式电压调节器是如何工作的？

1. By alternating the output between positive and negative voltages 通过在正电压和负电压之间交替输出
2. By varying the duty cycle of pulses input to a filter 通过改变输入到滤波器的脉冲的占空比
3. By varying the conductivity of a pass element 通过改变通道元件的电导率
4. By switching between two Zener diode reference voltages 通过在两个齐纳二极管参考电压之间切换

E7D03. What device is used as a stable voltage reference? 什么设备被用作稳定的电压参考？

1. A Zener diode 齐纳二极管
2. A digital-to-analog converter 数字模拟转换器
3. An SCR SCR
4. An analog-to-digital converter 模数转换器

E7D04. Which of the following describes a three-terminal voltage regulator? 以下哪项描述了三端电压调节器？

1. A series current source A系列电流源
2. A series regulator A系列调节器
3. A shunt regulator 并联调节器
4. A shunt current source 分流电流源

E7D05. Which of the following types of linear voltage regulator operates by loading the unregulated voltage source? 以下哪种类型的线性电压调节器通过加载未调节的电压源进行操作？

1. A constant current source 恒流源
2. A series regulator A系列调节器
3. A shunt current source 分流电流源
4. A shunt regulator 并联调节器

E7D06. What is the purpose of Q1 in the circuit shown in Figure E7-2? 图E7-2所示电路中Q1的用途是什么？

1. It provides negative feedback to improve regulation 它提供了负面反馈以改善监管
2. It provides a constant load for the voltage source 它为电压源提供恒定负载
3. It controls the current to keep the output voltage constant 它控制电流以保持输出电压恒定
4. It provides regulation by switching or “chopping” the input DC voltage 它通过切换或“斩波”输入直流电压来提供调节

E7D07. What is the purpose of C2 in the circuit shown in Figure E7-2? 图E7-2所示电路中C2的用途是什么？

1. It bypasses rectifier output ripple around D1 它绕过D1周围的整流器输出纹波
2. It is a brute force filter for the output 它是输出的强力过滤器
3. To prevent self-oscillation 防止自激振荡
4. To provide fixed DC bias for Q1 为Q1提供固定的直流偏压

E7D08. What type of circuit is shown in Figure E7-2? 图E7-2中显示了哪种类型的电路？

1. Switching voltage regulator 开关电压调节器
2. Common emitter amplifier 共射极放大器
3. Linear voltage regulator 线性电压调节器
4. Common base amplifier 共基极放大器

E7D09. How is battery operating time calculated? 电池工作时间是如何计算的？

1. Average current divided by capacity in amp-hours 平均电流除以容量（安培小时）
2. Average current divided by internal resistance 平均电流除以内阻
3. Capacity in amp-hours divided by average current 容量（安培小时）除以平均电流
4. Internal resistance divided by average current 内阻除以平均电流

E7D10. Why is a switching type power supply less expensive and lighter than an equivalent linear power supply? 为什么开关式电源比等效的线性电源更便宜、更轻？

1. The inverter design does not require an output filter circuit 逆变器设计不需要输出滤波电路
2. The control circuitry uses less current, therefore smaller heat sinks are required 控制电路使用较少的电流，因此需要较小的散热器
3. The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output 高频逆变器的设计使用更小的变压器和滤波器组件来实现等效功率输出
4. It recovers power from the unused portion of the AC cycle, thus using fewer components 它从交流循环的未使用部分恢复电力，从而使用更少的组件

E7D11. What is the purpose of an inverter connected to a solar panel output? 连接到太阳能电池板输出的逆变器的用途是什么？

1. Reduce AC ripple on the output 减少输出上的交流纹波
2. Maintain voltage with varying illumination levels 在不同照明水平下保持电压
3. Prevent discharge when panel is not illuminated 面板不亮时防止放电
4. Convert the panel’s output from DC to AC 将面板的输出从直流转换为交流

E7D12. What is the dropout voltage of a linear voltage regulator? 线性电压调节器的压降是多少？

1. Minimum input voltage for rated power dissipation 额定功耗的最小输入电压
2. Maximum output voltage drop when the input voltage is varied over its specified range 当输入电压在其指定范围内变化时的最大输出电压降
3. Minimum input-to-output voltage required to maintain regulation 维持调节所需的最小输入输出电压
4. Maximum that the output voltage may decrease at rated load 输出电压在额定负载下可能降低的最大值

E7D13. Which of the following calculates power dissipated by a series linear voltage regulator? 以下哪项计算串联线性电压调节器消耗的功率？

1. Input voltage multiplied by input current 输入电压乘以输入电流
2. Input voltage divided by output current 输入电压除以输出电流
3. Voltage difference from input to output multiplied by output current 输入到输出的电压差乘以输出电流
4. Output voltage multiplied by output current 输出电压乘以输出电流

E7D14. What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series? 在串联的电源滤波电容器之间连接等值电阻器的目的是什么？

1. Equalize the voltage across each capacitor 均衡每个电容器两端的电压
2. Discharge the capacitors when voltage is removed 消除电压后，使电容器放电
3. Provide a minimum load on the supply 在电源上提供最小负载
4. All these choices are correct 所有这些选择都是正确的

E7D15. What is the purpose of a step-start circuit in a high-voltage power supply? 高压电源中的步进启动电路的用途是什么？

1. To provide a dual-voltage output for reduced power applications 为低功耗应用提供双电压输出
2. To compensate for variations of the incoming line voltage 补偿进线电压的变化
3. To prevent arcing across the input power switch or relay contacts 防止输入电源开关或继电器触点产生电弧
4. To allow the filter capacitors to charge gradually 使滤波电容器逐渐充电

E7E01. Which of the following can be used to generate FM phone signals? 以下哪项可用于生成调频电话信号？

1. Balanced modulation of the audio amplifier 音频放大器的平衡调制
2. Reactance modulation of a local oscillator 本地振荡器的电抗调制
3. Reactance modulation of the final amplifier 末级放大器的电抗调制
4. Balanced modulation of a local oscillator 本地振荡器的平衡调制

E7E02. What is the function of a reactance modulator? 电抗调制器的功能是什么？

1. Produce PM or FM signals by varying a resistance 通过改变电阻产生PM或FM信号
2. Produce AM signals by varying an inductance 通过改变电感产生AM信号
3. Produce AM signals by varying a resistance 通过改变电阻产生AM信号
4. Produce PM or FM signals by varying a capacitance 通过改变电容产生PM或FM信号

E7E03. What is a frequency discriminator? 什么是频率鉴别器？

1. An FM generator circuit 调频发生器电路
2. A circuit for filtering closely adjacent signals 一种用于对相邻信号进行滤波的电路
3. An automatic band-switching circuit 一种自动波段切换电路
4. A circuit for detecting FM signals 一种用于检测调频信号的电路

E7E04. What is one way to produce a single-sideband phone signal? 产生单边带电话信号的一种方法是什么？

1. Use a balanced modulator followed by a filter 使用平衡调制器和滤波器
2. Use a reactance modulator followed by a mixer 使用电抗调制器，然后使用混频器
3. Use a loop modulator followed by a mixer 使用环路调制器，然后使用混频器
4. Use a product detector with a DSB signal 使用带有DSB信号的产品检测器

E7E05. What is added to an FM speech channel to boost the higher audio frequencies? 调频语音频道增加了什么来提高音频频率？

1. A de-emphasis network 去加重网络
2. A harmonic enhancer 谐波增强器
3. A heterodyne enhancer 外差增强器
4. A pre-emphasis network 预加重网络

E7E06. Why is de-emphasis used in FM communications receivers? 为什么在调频通信接收机中使用去加重？

1. For compatibility with transmitters using phase modulation 与使用相位调制的变送器兼容
2. To reduce impulse noise reception 减少脉冲噪声接收
3. For higher efficiency 为了更高的效率
4. To remove third-order distortion products 去除三阶失真产物

E7E07. What is meant by the term “baseband” in radio communications? 无线电通信中的“基带”一词是什么意思？

1. The lowest frequency band that the transmitter or receiver covers 发射机或接收机覆盖的最低频带
2. The frequency range occupied by a message signal prior to modulation 调制前消息信号所占的频率范围
3. The unmodulated bandwidth of the transmitted signal 传输信号的未调制带宽
4. The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency 调频发射机中的基本振荡器频率，它被相乘以增加偏差和载波频率

E7E08. What are the principal frequencies that appear at the output of a mixer? 混频器输出端出现的主频率是多少？

1. Two and four times the input frequency 输入频率的两倍和四倍
2. The square root of the product of input frequencies 输入频率乘积的平方根
3. The two input frequencies along with their sum and difference frequencies 两个输入频率及其和频和差频
4. 1.414 and 0.707 times the input frequency 输入频率的1.414倍和0.707倍

E7E09. What occurs when the input signal levels to a mixer are too high? 当混频器的输入信号电平过高时会发生什么？

1. Spurious mixer products are generated 产生虚假的混合器产品
2. Mixer blanking occurs 混合器出现下料
3. Automatic limiting occurs 发生自动限制
4. Excessive AGC voltage levels are generated 产生过大的AGC电压电平

E7E10. How does a diode envelope detector function? 二极管包络检波器是如何工作的？

1. By rectification and filtering of RF signals 通过RF信号的整流和滤波
2. By breakdown of the Zener voltage 通过齐纳电压的击穿
3. By mixing signals with noise in the transition region of the diode 通过在二极管的过渡区将信号与噪声混合
4. By sensing the change of reactance in the diode with respect to frequency 通过感应二极管中电抗相对于频率的变化

E7E11. Which type of detector is used for demodulating SSB signals? 哪种类型的检测器用于解调SSB信号？

1. Discriminator 鉴别器
2. Phase detector 相位检测器
3. Product detector 产品检测器
4. Phase comparator 相位比较器

E7F01. What is meant by “direct sampling” in software defined radios? 软件定义无线电中的“直接采样”是什么意思？

1. Software is converted from source code to object code during operation of the receiver 在接收器的操作过程中，软件从源代码转换为目标代码
2. I and Q signals are generated by digital processing without the use of RF amplification I和Q信号是在不使用射频放大的情况下通过数字处理生成的
3. Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal 输入RF由模数转换器数字化，而不与本地振荡器信号混合
4. A switching mixer is used to generate I and Q signals directly from the RF input 开关混频器用于直接从RF输入生成I和Q信号

E7F02. What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal? 什么样的数字信号处理音频滤波器用于从接收到的SSB信号中去除不需要的噪声？

1. An adaptive filter 自适应滤波器
2. A crystal-lattice filter 晶格滤波器
3. A Hilbert-transform filter 希尔伯特变换滤波器
4. A phase-inverting filter 反相滤波器

E7F03. What type of digital signal processing filter is used to generate an SSB signal? 什么类型的数字信号处理滤波器用于生成SSB信号？

1. An adaptive filter 自适应滤波器
2. A notch filter 陷波滤波器
3. A Hilbert-transform filter 希尔伯特变换滤波器
4. An elliptical filter 椭圆滤波器

E7F04. Which method generates an SSB signal using digital signal processing? 哪种方法使用数字信号处理生成SSB信号？

1. Mixing products are converted to voltages and subtracted by adder circuits 混合产物被转换为电压，并由加法器电路减去
2. A frequency synthesizer removes unwanted sidebands 频率合成器去除不需要的边带
3. Varying quartz crystal characteristics are emulated in digital form 以数字形式模拟不同的石英晶体特性
4. Signals are combined in quadrature phase relationship 信号以正交相位关系组合

E7F05. How frequently must an analog signal be sampled to be accurately reproduced? 模拟信号必须多久采样一次才能准确再现？

1. At least half the rate of the highest frequency component of the signal 至少为信号最高频率分量速率的一半
2. At least twice the rate of the highest frequency component of the signal 至少是信号最高频率分量速率的两倍
3. At the same rate as the highest frequency component of the signal 以与信号的最高频率分量相同的速率
4. At four times the rate of the highest frequency component of the signal 以信号最高频率分量的四倍速率

E7F06. What is the minimum number of bits required to sample a signal with a range of 1 volt at a resolution of 1 millivolt? 以1毫伏的分辨率对1伏范围的信号进行采样所需的最小位数是多少？

1. 4 bits 4位
2. 6 bits 6位
3. 8 bits 8位
4. 10 bits 10位

E7F07. What function is performed by a Fast Fourier Transform? 快速傅立叶变换执行什么功能？

1. Converting analog signals to digital form 将模拟信号转换为数字形式
2. Converting digital signals to analog form 将数字信号转换为模拟形式
3. Converting signals from the time domain to the frequency domain 将信号从时域转换为频域
4. Converting signals from the frequency domain to the time domain 将信号从频域转换为时域

E7F08. What is the function of decimation? 抽取的功能是什么？

1. Converting data to binary-coded decimal form 将数据转换为二进制编码的十进制形式
2. Reducing the effective sample rate by removing samples 通过移除样本降低有效采样率
3. Attenuating the signal 减弱信号
4. Removing unnecessary significant digits 删除不必要的有效数字

E7F09. Why is an anti-aliasing filter required in a decimator? 为什么抽取器中需要抗混叠滤波器？

1. It removes high-frequency signal components that would otherwise be reproduced as lower frequency components 它去除了高频信号分量，否则这些分量将被再现为低频分量
2. It peaks the response of the decimator, improving bandwidth 它使抽取器的响应达到峰值，提高了带宽
3. It removes low-frequency signal components to eliminate the need for DC restoration 它去除了低频信号分量，消除了直流恢复的需要
4. It notches out the sampling frequency to avoid sampling errors 它降低了采样频率以避免采样误差

E7F10. What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a direct-sampling software defined radio (SDR)? 接收器模数转换的哪个方面决定了直接采样软件定义无线电（SDR）的最大接收带宽？

1. Sample rate 采样率
2. Sample width in bits 样本宽度（以位为单位）
3. Integral non-linearity 积分非线性
4. Differential non-linearity 微分非线性

E7F11. What sets the minimum detectable signal level for a direct-sampling software defined receiver in the absence of atmospheric or thermal noise? 在没有大气或热噪声的情况下，是什么设置了直接采样软件定义接收器的最小可检测信号电平？

1. Sample clock phase noise 采样时钟相位噪声
2. Reference voltage level and sample width in bits 参考电压电平和采样宽度（以位为单位）
3. Data storage transfer rate 数据存储传输速率
4. Missing codes and jitter 代码缺失和抖动

E7F12. Which of the following is generally true of Finite Impulse Response (FIR) filters? 以下哪一项通常适用于有限脉冲响应（FIR）滤波器？

1. FIR filters can delay all frequency components of the signal by the same amount FIR滤波器可以将信号的所有频率分量延迟相同的量
2. FIR filters are easier to implement for a given set of passband rolloff requirements 对于给定的一组通带滚降要求，FIR滤波器更容易实现
3. FIR filters can respond faster to impulses FIR滤波器可以更快地响应脉冲
4. All these choices are correct 所有这些选择都是正确的

E7F13. What is the function of taps in a digital signal processing filter? 数字信号处理滤波器中抽头的功能是什么？

1. To reduce excess signal pressure levels 降低过量信号压力水平
2. Provide access for debugging software 提供调试软件的访问权限
3. Select the point at which baseband signals are generated 选择生成基带信号的点
4. Provide incremental signal delays for filter algorithms 为滤波器算法提供增量信号延迟

E7F14. Which of the following would allow a digital signal processing filter to create a sharper filter response? 以下哪项可以使数字信号处理滤波器产生更清晰的滤波器响应？

1. Higher data rate 更高的数据速率
2. More taps 更多抽头
3. Lower Q 较低Q
4. Double-precision math routines 双精度数学例程

E7G01. What is the typical output impedance of an op-amp? 运算放大器的典型输出阻抗是多少？

1. Very low 非常低
2. Very high 非常高
3. 100 ohms 100欧姆
4. 10,000 ohms 10000欧姆

E7G02. What is the frequency response of the circuit in E7-3 if a capacitor is added across the feedback resistor? 如果在反馈电阻器两端添加电容器，E7-3中电路的频率响应是多少？

1. High-pass filter 高通滤波器
2. Low-pass filter 低通滤波器
3. Band-pass filter 带通滤波器
4. Notch filter 陷波滤波器

E7G03. What is the typical input impedance of an op-amp? 运算放大器的典型输入阻抗是多少？

1. 100 ohms 100欧姆
2. 10,000 ohms 10000欧姆
3. Very low 非常低
4. Very high 非常高

E7G04. What is meant by the term “op-amp input offset voltage”? 术语“运算放大器输入偏移电压”是什么意思？

1. The output voltage of the op-amp minus its input voltage 运算放大器的输出电压减去其输入电压
2. The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage 运算放大器的输出电压与下一级所需的输入电压之间的差值
3. The differential input voltage needed to bring the open loop output voltage to zero 使开环输出电压为零所需的差分输入电压
4. The potential between the amplifier input terminals of the op-amp in an open loop condition 开环条件下运算放大器的放大器输入端子之间的电位

E7G05. How can unwanted ringing and audio instability be prevented in an op-amp audio filter? 如何在运算放大器音频滤波器中防止不必要的振铃和音频不稳定？

1. Restrict both gain and Q 限制增益和Q
2. Restrict gain but increase Q 限制增益但增加Q
3. Restrict Q but increase gain 限制Q但增加增益
4. Increase both gain and Q 增加增益和Q

E7G06. What is the gain-bandwidth of an operational amplifier? 运算放大器的增益带宽是多少？

1. The maximum frequency for a filter circuit using that type of amplifier 使用该类型放大器的滤波器电路的最大频率
2. The frequency at which the open-loop gain of the amplifier equals one 放大器的开环增益等于1的频率
3. The gain of the amplifier at a filter’s cutoff frequency 滤波器截止频率下放大器的增益
4. The frequency at which the amplifier’s offset voltage is zero 放大器的偏移电压为零的频率

E7G07. What voltage gain can be expected from the circuit in Figure E7-3 when R1 is 10 ohms and RF is 470 ohms? 当R1为10欧姆，RF为470欧姆时，图E7-3中电路的预期电压增益是多少？

1. 0.21 0.21
2. 4700 4700
3. 47 47
4. 24 24

E7G08. How does the gain of an ideal operational amplifier vary with frequency? 理想的运算放大器的增益是如何随频率变化的？

1. It increases linearly with increasing frequency 它随着频率的增加而线性增加
2. It decreases linearly with increasing frequency 它随着频率的增加而线性下降
3. It decreases logarithmically with increasing frequency 它随着频率的增加呈对数递减
4. It does not vary with frequency 它不随频率变化

E7G09. What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1,000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input? 如果R1为1000欧姆，RF为10000欧姆，并且0.23伏直流电施加到输入端，那么图E7-3所示电路的输出电压是多少？

1. 0.23 volts 0.23伏
2. 2.3 volts 2.3伏
3. -0.23 volts -0.23伏
4. -2.3 volts -2.3伏

E7G10. What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1,800 ohms and RF is 68 kilohms? 当R1为1800欧姆，RF为68千欧姆时，图E7-3中电路的绝对电压增益是多少？

1. 1 1
2. 0.03 0.03
3. 38 38
4. 76 76

E7G11. What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3,300 ohms and RF is 47 kilohms? 当R1为3300欧姆，RF为47千欧姆时，图E7-3中电路的绝对电压增益是多少？

1. 28 28
2. 14 14
3. 7 7
4. 0.07 0.07

E7G12. What is an operational amplifier? 什么是运算放大器？

1. A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance 具有极高输入阻抗和极低输出阻抗的高增益直接耦合差分放大器
2. A digital audio amplifier whose characteristics are determined by components external to the amplifier 一种数字音频放大器，其特性由放大器外部的组件决定
3. An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit 一种放大器，用于将调频业余信号的平均输出提高到法定限度
4. A RF amplifier used in the UHF and microwave regions 用于超高频和微波区域的RF放大器

E7H01. What are three common oscillator circuits? 三种常见的振荡器电路是什么？

1. Taft, Pierce, and negative feedback 塔夫脱、皮尔斯和负面反馈
2. Pierce, Fenner, and Beane 皮尔斯、芬纳和比恩
3. Taft, Hartley, and Pierce 塔夫脱、哈特利和皮尔斯
4. Colpitts, Hartley, and Pierce Colpitts、Hartley和Pierce

E7H02. What is a microphonic? 什么是麦克风？

1. An IC used for amplifying microphone signals 一种用于放大麦克风信号的IC
2. Distortion caused by RF pickup on the microphone cable 麦克风电缆上的RF拾波引起的失真
3. Changes in oscillator frequency caused by mechanical vibration 机械振动引起的振荡器频率变化
4. Excess loading of the microphone by an oscillator 振荡器对麦克风的过度负载

E7H03. What is a phase-locked loop? 什么是锁相环？

1. An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator 一种由比率检测器、电抗调制器和压控振荡器组成的电子伺服回路
2. An electronic circuit also known as a monostable multivibrator 一种也称为单稳态多谐振荡器的电子电路
3. An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator 一种电子伺服回路，由相位检测器、低通滤波器、压控振荡器和稳定参考振荡器组成
4. An electronic circuit consisting of a precision push-pull amplifier with a differential phase input 一种由具有差分相位输入的精密推挽放大器组成的电子电路

E7H04. How is positive feedback supplied in a Colpitts oscillator? 如何在Colpitts振荡器中提供正反馈？

1. Through a tapped coil 通过抽头线圈
2. Through link coupling 贯穿联轴节
3. Through a capacitive divider 通过电容分压器
4. Through a neutralizing capacitor 通过一个中和电容器

E7H05. How is positive feedback supplied in a Pierce oscillator? 皮尔斯振荡器是如何提供正反馈的？

1. Through a tapped coil 通过抽头线圈
2. Through link coupling 贯穿联轴节
3. Through a neutralizing capacitor 通过一个中和电容器
4. Through a quartz crystal 透过石英晶体

E7H06. Which of these functions can be performed by a phase-locked loop? 这些功能中的哪一个可以由锁相环执行？

1. Wide-band AF and RF power amplification 宽带AF和RF功率放大
2. Frequency synthesis and FM demodulation 频率合成和调频解调
3. Photovoltaic conversion and optical coupling 光伏转换和光耦合
4. Comparison of two digital input signals and digital pulse counting 两种数字输入信号的比较和数字脉冲计数

E7H07. How can an oscillator’s microphonic responses be reduced? 如何降低振荡器的微音响应？

1. Use NP0 capacitors 使用NP0电容器
2. Reduce noise on the oscillator’s power supply 降低振荡器电源上的噪声
3. Increase the gain 增加增益
4. Mechanically isolate the oscillator circuitry from its enclosure 将振荡器电路与其外壳机械隔离

E7H08. Which of the following components can be used to reduce thermal drift in crystal oscillators? 以下哪些组件可用于减少晶体振荡器中的热漂移？

1. NP0 capacitors NP0电容器
2. Toroidal inductors 环形电感器
3. Wirewound resistors 线绕电阻器
4. Non-inductive resistors 无感电阻器

E7H09. What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital-to-analog converter, and a low-pass anti-alias filter? 什么类型的频率合成器电路使用相位累加器、查找表、数模转换器和低通抗混叠滤波器？

1. A direct digital synthesizer 一种直接数字合成器
2. A hybrid synthesizer 一种混合合成器
3. A phase-locked loop synthesizer 一种锁相环合成器
4. A direct conversion synthesizer 一种直接转换合成器

E7H10. What information is contained in the lookup table of a direct digital synthesizer (DDS)? 直接数字合成器（DDS）的查找表中包含哪些信息？

1. The phase relationship between a reference oscillator and the output waveform 参考振荡器和输出波形之间的相位关系
2. Amplitude values that represent the desired waveform 表示所需波形的振幅值
3. The phase relationship between a voltage-controlled oscillator and the output waveform 压控振荡器与输出波形之间的相位关系
4. Frequently used receiver and transmitter frequencies 常用的接收机和发射机频率

E7H11. What are the major spectral impurity components of direct digital synthesizers? 直接数字合成器的主要光谱杂质成分是什么？

1. Broadband noise 宽带噪声
2. Digital conversion noise 数字转换噪声
3. Spurious signals at discrete frequencies 离散频率的杂散信号
4. Harmonics of the local oscillator 本地振荡器的谐波

E7H12. Which of the following ensures that a crystal oscillator operates on the frequency specified by the crystal manufacturer? 以下哪项可确保晶体振荡器在晶体制造商规定的频率下工作？

1. Provide the crystal with a specified parallel inductance 为晶体提供指定的并联电感
2. Provide the crystal with a specified parallel capacitance 为晶体提供指定的并联电容
3. Bias the crystal at a specified voltage 在指定电压下偏置晶体
4. Bias the crystal at a specified current 以指定的电流偏置晶体

E7H13. Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception? 以下哪项是提供微波发射和接收所需的高精度和稳定振荡器的技术？

1. Use a GPS signal reference 使用GPS信号参考
2. Use a rubidium stabilized reference oscillator 使用铷稳定的参考振荡器
3. Use a temperature-controlled high Q dielectric resonator 使用温度控制的高Q介质谐振器
4. All these choices are correct 所有这些选择都是正确的

E8A01. What technique shows that a square wave is made up of a sine wave and its odd harmonics? 什么技术可以证明方波是由正弦波及其奇次谐波组成的？

1. Fourier analysis 傅立叶分析
2. Vector analysis 矢量分析
3. Numerical analysis 数值分析
4. Differential analysis 差异分析

E8A02. Which of the following is a type of analog-to-digital conversion? 以下哪项是一种模数转换？

1. Successive approximation 逐次逼近
2. Harmonic regeneration 谐波再生
3. Level shifting 水平移动
4. Phase reversal 相位反转

E8A04. What is “dither” with respect to analog-to-digital converters? 关于模数转换器，什么是“抖动”？

1. An abnormal condition where the converter cannot settle on a value to represent the signal 转换器无法确定表示信号的值的异常情况
2. A small amount of noise added to the input signal to reduce quantization noise 将少量噪声添加到输入信号以减少量化噪声
3. An error caused by irregular quantization step size 由不规则量化步长引起的误差
4. A method of decimation by randomly skipping samples 一种随机跳过样本的抽取方法

E8A05. What is the benefit of making voltage measurements with a true-RMS calculating meter? 使用真正的RMS计算仪表进行电压测量有什么好处？

1. An inverse Fourier transform can be used 可以使用傅立叶逆变换
2. The signal’s RMS noise factor is also calculated 还计算了信号的RMS噪声因子
3. The calculated RMS value can be converted directly into phasor form 计算的RMS值可以直接转换为相量形式
4. RMS is measured for both sinusoidal and non-sinusoidal signals 测量正弦和非正弦信号的RMS

E8A06. What is the approximate ratio of PEP-to-average power in an unprocessed single-sideband phone signal? 在未处理的单边带电话信号中，PEP与平均功率的近似比率是多少？

1. 2.5 to 1 2.5比1
2. 25 to 1 25比1
3. 1 to 1 1到1
4. 13 to 1 13到1

E8A07. What determines the PEP-to-average power ratio of an unprocessed single-sideband phone signal? 是什么决定了未处理的单边带电话信号的PEP与平均功率比？

1. The frequency of the modulating signal 调制信号的频率
2. Speech characteristics 语音特征
3. The degree of carrier suppression 载波抑制程度
4. Amplifier gain 放大器增益

E8A08. Why are direct or flash conversion analog-to-digital converters used for a software defined radio? 为什么直接或闪存转换模数转换器用于软件定义的收音机？

1. Very low power consumption decreases frequency drift 非常低的功耗降低了频率漂移
2. Immunity to out-of-sequence coding reduces spurious responses 抗序列外编码降低杂散响应
3. Very high speed allows digitizing high frequencies 非常高的速度允许数字化高频
4. All these choices are correct 所有这些选择都是正确的

E8A09. How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution? 一个8位分辨率的模数转换器可以编码多少个不同的输入电平？

1. 8 8
2. 8 multiplied by the gain of the input amplifier 8乘以输入放大器的增益
3. 256 divided by the gain of the input amplifier 256除以输入放大器的增益
4. 256 256

E8A10. What is the purpose of a low-pass filter used at the output of a digital-to-analog converter? 在数模转换器的输出端使用低通滤波器的目的是什么？

1. Lower the input bandwidth to increase the effective resolution 降低输入带宽以提高有效分辨率
2. Improve accuracy by removing out-of-sequence codes from the input 通过从输入中删除无序代码来提高准确性
3. Remove spurious sampling artifacts from the output signal 从输出信号中去除杂散采样伪影
4. All these choices are correct 所有这些选择都是正确的

E8A11. Which of the following is a measure of the quality of an analog-to-digital converter? 以下哪项是衡量模数转换器质量的指标？

1. Total harmonic distortion 总谐波失真
2. Peak envelope power 峰值包络功率
3. Reciprocal mixing 相互混合
4. Power factor 功率因数

E8B01. What is the modulation index of an FM signal? 调频信号的调制指数是多少？

1. The ratio of frequency deviation to modulating signal frequency 频率偏差与调制信号频率之比
2. The ratio of modulating signal amplitude to frequency deviation 调制信号振幅与频率偏差之比
3. The modulating signal frequency divided by the bandwidth of the transmitted signal 调制信号频率除以传输信号的带宽
4. The bandwidth of the transmitted signal divided by the modulating signal frequency 传输信号的带宽除以调制信号频率

E8B02. How does the modulation index of a phase-modulated emission vary with RF carrier frequency? 相位调制发射的调制指数如何随射频载波频率而变化？

1. It increases as the RF carrier frequency increases 它随着射频载波频率的增加而增加
2. It decreases as the RF carrier frequency increases 它随着射频载波频率的增加而减小
3. It varies with the square root of the RF carrier frequency 它随射频载波频率的平方根而变化
4. It does not depend on the RF carrier frequency 它不取决于射频载波频率

E8B03. What is the modulation index of an FM phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency if the highest modulating frequency is 1000 Hz? 如果最高调制频率为1000赫兹，那么载波频率两侧最大频率偏差为3000赫兹的调频电话信号的调制指数是多少？

1. 3 3
2. 0.3 0.3
3. 6 6
4. 0.6 0.6

E8B04. What is the modulation index of an FM phone signal having a maximum carrier deviation of plus or minus 6 kHz if the highest modulating frequency is 2 kHz? 如果最高调制频率为2kHz，则最大载波偏差为正或负6kHz的调频电话信号的调制指数是多少？

1. 0.3 0.3
2. 3 3
3. 0.6 0.6
4. 6 6

E8B05. What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 5 kHz if the highest modulation frequency is 3 kHz? 如果最高调制频率为3kHz，则具有正或负5kHz的最大频率摆动的调频电话信号的偏差比是多少？

1. 6 6
2. 0.167 0.167
3. 0.6 0.6
4. 1.67 1.67

E8B06. What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 7.5 kHz if the highest modulation frequency is 3.5 kHz? 如果最高调制频率为3.5 kHz，则具有正或负7.5 kHz的最大频率摆动的调频电话信号的偏差率是多少？

1. 2.14 2.14
2. 0.214 0.214
3. 0.47 0.47
4. 47 47

E8B07. Orthogonal frequency-division multiplexing (OFDM) is a technique used for which types of amateur communication? 正交频分复用（OFDM）是一种用于哪种类型的业余通信的技术？

1. Digital modes 数字模式
2. Extremely low-power contacts 极低功率触点
3. EME 电磁环境
4. OFDM signals are not allowed on amateur bands 业余频段不允许使用OFDM信号

E8B08. What describes orthogonal frequency-division multiplexing (OFDM)? 什么描述正交频分复用（OFDM）？

1. A frequency modulation technique that uses non-harmonically related frequencies 一种使用非谐波相关频率的频率调制技术
2. A bandwidth compression technique using Fourier transforms 一种使用傅立叶变换的带宽压缩技术
3. A digital mode for narrow-band, slow-speed transmissions 窄带低速传输的数字模式
4. A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference 一种数字调制技术，使用频率选择为避免符号间干扰的子载波

E8B09. What is deviation ratio? 偏差率是多少？

1. The ratio of the audio modulating frequency to the center carrier frequency 音频调制频率与中心载波频率的比率
2. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency 最大载波频率偏差与最高音频调制频率的比率
3. The ratio of the carrier center frequency to the audio modulating frequency 载波中心频率与音频调制频率之比
4. The ratio of the highest audio modulating frequency to the average audio modulating frequency 最高音频调制频率与平均音频调制频率的比率

E8B10. What is frequency division multiplexing (FDM)? 什么是频分复用（FDM）？

1. The transmitted signal jumps from band to band at a predetermined rate 传输的信号以预定的速率从一个频带跳到另一个频带
2. Dividing the transmitted signal into separate frequency bands that each carry a different data stream 将传输的信号划分为单独的频带，每个频带携带不同的数据流
3. The transmitted signal is divided into packets of information 传输的信号被分成信息包
4. Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter 两个或多个信息流被合并到数字组合器中，然后数字组合器对发射机进行脉冲位置调制

E8B11. What is digital time division multiplexing? 什么是数字时分复用？

1. Two or more data streams are assigned to discrete sub-carriers on an FM transmitter 两个或多个数据流被分配给FM发射机上的离散子载波
2. Two or more signals are arranged to share discrete time slots of a data transmission 两个或多个信号被安排为共享数据传输的离散时隙
3. Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier 两个或多个数据流通过作为子载波的传输时间来共享同一信道
4. Two or more signals are quadrature modulated to increase bandwidth efficiency 对两个或多个信号进行正交调制以提高带宽效率

E8C01. What is Quadrature Amplitude Modulation or QAM? 什么是正交幅度调制或QAM？

1. A technique for digital data compression used in digital television which removes redundancy in the data by comparing bit amplitudes 一种用于数字电视的数字数据压缩技术，通过比较比特幅度来消除数据中的冗余
2. Transmission of data by modulating the amplitude of two carriers of the same frequency but 90 degrees out of phase 通过调制频率相同但相位相差90度的两个载波的振幅来传输数据
3. A method of performing single sideband modulation by shifting the phase of the carrier and modulation components of the signal 一种通过移动信号的载波和调制分量的相位来进行单边带调制的方法
4. A technique for analog modulation of television video signals using phase modulation and compression 一种利用相位调制和压缩对电视视频信号进行模拟调制的技术

E8C02. What is the definition of symbol rate in a digital transmission? 数字传输中符号率的定义是什么？

1. The number of control characters in a message packet 消息包中的控制字符数
2. The maximum rate at which the forward error correction code can make corrections 前向纠错码可以进行校正的最大速率
3. The rate at which the waveform changes to convey information 波形为传递信息而变化的速率
4. The number of characters carried per second by the station-to-station link 站点到站点链接每秒携带的字符数

E8C03. Why should the phase of a PSK signal be changed at the zero crossing of the RF signal? 为什么PSK信号的相位应该在RF信号的过零点处改变？

1. To minimize bandwidth 最小化带宽
2. To simplify modulation 简化调制
3. To improve carrier suppression 提高载波抑制
4. All these choices are correct 所有这些选择都是正确的

E8C04. What technique minimizes the bandwidth of a PSK31 signal? 什么技术可以最大限度地减少PSK31信号的带宽？

1. Zero-sum character encoding 零和字符编码
2. Reed-Solomon character encoding 里德-所罗门字符编码
3. Use of sinusoidal data pulses 正弦数据脉冲的使用
4. Use of linear data pulses 线性数据脉冲的使用

E8C05. What is the approximate bandwidth of a 13-WPM International Morse Code transmission? 13-WPM国际莫尔斯电码传输的大致带宽是多少？

1. 13 Hz 13赫兹
2. 26 Hz 26赫兹
3. 52 Hz 52赫兹
4. 104 Hz 104赫兹

E8C06. What is the bandwidth of an FT8 signal? FT8信号的带宽是多少？

1. 10 Hz 10赫兹
2. 50 Hz 50赫兹
3. 600 Hz 600赫兹
4. 2.4 kHz 2.4千赫

E8C07. What is the bandwidth of a 4,800-Hz frequency shift, 9,600-baud ASCII FM transmission? 4800赫兹频移、9600波特ASCII调频传输的带宽是多少？

1. 15.36 kHz 15.36千赫
2. 9.6 kHz 9.6千赫
3. 4.8 kHz 4.8千赫
4. 5.76 kHz 5.76千赫

E8C08. How does ARQ accomplish error correction? ARQ是如何完成纠错的？

1. Special binary codes provide automatic correction 特殊二进制代码提供自动校正
2. Special polynomial codes provide automatic correction 特殊的多项式代码提供自动校正
3. If errors are detected, redundant data is substituted 如果检测到错误，则替换冗余数据
4. If errors are detected, a retransmission is requested 如果检测到错误，则请求重新传输

E8C09. Which digital code allows only one bit to change between sequential code values? 哪种数字代码只允许一位在顺序代码值之间变化？

1. Binary Coded Decimal Code 二进制编码的十进制代码
2. Extended Binary Coded Decimal Interchange Code 扩展二进制编码十进制交换码
3. Extended ASCII 扩展ASCII
4. Gray code 格雷码

E8C10. How can data rate be increased without increasing bandwidth? 如何在不增加带宽的情况下提高数据速率？

1. It is impossible 这是不可能的
2. Increasing analog-to-digital conversion resolution 提高模数转换分辨率
3. Using a more efficient digital code 使用更高效的数字代码
4. Using forward error correction 使用前向纠错

E8C11. What is the relationship between symbol rate and baud? 符号速率和波特之间的关系是什么？

1. They are the same 他们是一样的
2. Baud is twice the symbol rate 波特率是符号速率的两倍
3. Baud rate is half the symbol rate 波特率是符号速率的一半
4. The relationship depends on the specific code used 关系取决于使用的特定代码

E8C12. What factors affect the bandwidth of a transmitted CW signal? 哪些因素会影响传输的CW信号的带宽？

1. IF bandwidth and Q 中频带宽和Q
2. Modulation index and output power 调制指数和输出功率
3. Keying speed and shape factor (rise and fall time) 键控速度和形状因子（上升和下降时间）
4. All these choices are correct 所有这些选择都是正确的

E8C13. What is described by the constellation diagram of a QAM or QPSK signal? QAM或QPSK信号的星座图描述了什么？

1. How many carriers may be present at the same time 可以同时存在多少个载波
2. The possible phase and amplitude states for each symbol 每个符号可能的相位和振幅状态
3. Frequency response of the signal stream 信号流的频率响应
4. The number of bits used for error correction in the protocol 协议中用于纠错的位数

E8C14. What type of addresses do nodes have in a mesh network? 网状网络中的节点有什么类型的地址？

1. Email 电子邮件
2. Trust server 信任服务器
3. Internet Protocol (IP) 互联网协议（IP）
4. Talk group 谈话小组

E8C15. What technique do individual nodes use to form a mesh network? 单个节点使用什么技术来形成网状网络？

1. Forward error correction and Viterbi codes 前向纠错和维特比码
2. Acting as store-and-forward digipeaters 充当存储和转发digipeater
3. Discovery and link establishment protocols 发现和链路建立协议
4. Custom code plugs for the local trunking systems 本地集群系统的自定义代码插件

E8D01. Why are received spread spectrum signals resistant to interference? 为什么接收到的扩频信号具有抗干扰性？

1. Signals not using the spread spectrum algorithm are suppressed in the receiver 不使用扩频算法的信号在接收器中被抑制
2. The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered 扩频发射机使用的高功率使其信号不容易被压倒
3. Built-in error correction codes minimize interference 内置纠错码可最大限度地减少干扰
4. If the receiver detects interference, it will signal the transmitter to change frequencies 如果接收机检测到干扰，它将向发射机发送信号以改变频率

E8D02. What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier? 什么扩频通信技术使用高速二进制比特流来移动RF载波的相位？

1. Frequency hopping 跳频
2. Direct sequence 直接序列
3. Binary phase-shift keying 二进制移相键控
4. Phase compandored spread spectrum 相位压扩扩频

E8D03. Which describes spread spectrum frequency hopping? 哪个描述扩频跳频？

1. If interference is detected by the receiver, it will signal the transmitter to change frequencies 如果接收机检测到干扰，它将向发射机发送信号以改变频率
2. RF signals are clipped to generate a wide band of harmonics which provides redundancy to correct errors RF信号被削波以产生宽带谐波，该宽带谐波提供冗余以校正误差
3. A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence 二进制比特流用于在伪随机序列中非常快速地移动RF载波的相位
4. Rapidly varying the frequency of a transmitted signal according to a pseudorandom sequence 根据伪随机序列快速改变发射信号的频率

E8D04. What is the primary effect of extremely short rise or fall time on a CW signal? 极短的上升或下降时间对CW信号的主要影响是什么？

1. More difficult to copy 更难复制
2. The generation of RF harmonics 射频谐波的产生
3. The generation of key clicks 按键点击的生成
4. More difficult to tune 更难调整

E8D05. What is the most common method of reducing key clicks? 减少按键点击的最常见方法是什么？

1. Increase keying waveform rise and fall times 增加键控波形的上升和下降时间
2. Insert low-pass filters at the transmitter output 在变送器输出处插入低通滤波器
3. Reduce keying waveform rise and fall times 减少键控波形的上升和下降时间
4. Insert high-pass filters at the transmitter output 在变送器输出处插入高通滤波器

E8D06. What is the advantage of including parity bits in ASCII characters? 在ASCII字符中包含奇偶校验位的优点是什么？

1. Faster transmission rate 更快的传输速率
2. Signal-to-noise ratio is improved 信噪比提高
3. A larger character set is available 可以使用更大的字符集
4. Some types of errors can be detected 可以检测到某些类型的错误

E8D07. What is a common cause of overmodulation of AFSK signals? AFSK信号过调制的常见原因是什么？

1. Excessive numbers of retries 重试次数过多
2. Excessive frequency deviation 频率偏差过大
3. Bit errors in the modem 调制解调器中的位错误
4. Excessive transmit audio levels 传输音频电平过高

E8D08. What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels? 什么参数可以评估输入音频电平过高导致的AFSK信号失真？

1. Signal-to-noise ratio 信噪比
2. Baud error rate 波特率错误率
3. Repeat Request Rate (RRR) 重复请求率（RRR）
4. Intermodulation Distortion (IMD) 互调失真（IMD）

E8D09. What is considered an acceptable maximum IMD level for an idling PSK signal? 空转PSK信号的可接受最大IMD水平是多少？

1. +5 dB +5分贝
2. +10 dB +10分贝
3. +15 dB +15分贝
4. -30 dB -30分贝

E8D10. What are some of the differences between the Baudot digital code and ASCII? Baudot数字代码和ASCII之间有哪些区别？

1. Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code Baudot每个字符使用4个数据位，ASCII使用7或8个；Baudot使用1个字符作为字母/数字移位码，ASCII没有字母/数字码
2. Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code Baudot每字符使用5个数据位，ASCII使用7或8个；Baudot使用2个字符作为字母/数字的移位码，ASCII没有字母/数字移位码
3. Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes Baudot每字符使用6个数据位，ASCII使用7或8个；Baudot没有字母/数字移位码，ASCII使用2个字母/数字的移位码
4. Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes Baudot每字符使用7个数据位，ASCII使用8个；Baudot没有字母/数字移位码，ASCII使用2个字母/数字的移位码

E8D11. What is one advantage of using ASCII code for data communications? 使用ASCII码进行数据通信的一个优点是什么？

1. It includes built-in error correction features 它包括内置的纠错功能
2. It contains fewer information bits per character than any other code 它每个字符包含的信息位比任何其他代码都少
3. It is possible to transmit both uppercase and lowercase text 可以同时传输大写和小写文本
4. It uses one character as a shift code to send numeric and special characters 它使用一个字符作为移位码来发送数字字符和特殊字符

E9A01. What is an isotropic radiator? 什么是各向同性散热器？

1. A calibrated, unidirectional antenna used to make precise antenna gain measurements 一种经过校准的单向天线，用于进行精确的天线增益测量
2. An omnidirectional, horizontally polarized, precisely calibrated antenna used to make field measurements of antenna gain 一种全向、水平极化、精确校准的天线，用于现场测量天线增益
3. A hypothetical, lossless antenna having equal radiation intensity in all directions used as a reference for antenna gain 一种假设的无损天线，在所有方向上具有相等的辐射强度，用作天线增益的参考
4. A spacecraft antenna used to direct signals toward Earth 一种用于将信号导向地球的航天器天线

E9A02. What is the effective radiated power (ERP) of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain? 具有150瓦发射机功率输出、2 dB馈线损耗、2.2 dB双工器损耗和7 dBd天线增益的中继站的有效辐射功率（ERP）是多少？

1. 469 watts 469瓦
2. 78.7 watts 78.7瓦
3. 420 watts 420瓦
4. 286 watts 286瓦

E9A03. What term describing total radiated power takes into account all gains and losses? 描述总辐射功率的哪个术语考虑了所有增益和损耗？

1. Power factor 功率因数
2. Half-power bandwidth 半功率带宽
3. Effective radiated power 有效辐射功率
4. Apparent power 视在功率

E9A04. Which of the following factors affect the feed point impedance of an antenna? 以下哪些因素会影响天线的馈电点阻抗？

1. Transmission line length 输电线路长度
2. Antenna height 天线高度
3. The settings of an antenna tuner at the transmitter 发射器上天线调谐器的设置
4. The input power level 输入功率电平

E9A05. What does the term “ground gain” mean? “地面增益”是什么意思？

1. The change in signal strength caused by grounding the antenna 天线接地引起的信号强度变化
2. The gain of the antenna with respect to a dipole at ground level 天线相对于地面偶极子的增益
3. To force net gain to 0 dB by grounding part of the antenna 通过将天线的一部分接地，使净增益达到0 dB
4. An increase in signal strength from ground reflections in the environment of the antenna 天线环境中地面反射信号强度的增加

E9A06. What is the effective radiated power (ERP) of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain? 具有200瓦发射机功率输出、4 dB馈线损耗、3.2 dB双工器损耗、0.8 dB循环器损耗和10 dBd天线增益的中继站的有效辐射功率（ERP）是多少？

1. 317 watts 317瓦
2. 2,000 watts 2000瓦
3. 126 watts 126瓦
4. 300 watts 300瓦

E9A07. What is the effective isotropic radiated power (EIRP) of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain? 具有200瓦发射机功率输出、2 dB馈线损耗、2.8 dB双工器损耗、1.2 dB循环器损耗和7 dBi天线增益的中继站的有效各向同性辐射功率（EIRP）是多少？

1. 159 watts 159瓦
2. 252 watts 252瓦
3. 632 watts 632瓦
4. 63.2 watts 63.2瓦

E9A08. Which frequency band has the smallest first Fresnel zone? 哪个频带的第一菲涅耳区最小？

1. 5.8 GHz 5.8千兆赫
2. 3.4 GHz 3.4千兆赫
3. 2.4 GHz
4. 900 MHz 900兆赫

E9A09. What is antenna efficiency? 什么是天线效率？

1. Radiation resistance divided by transmission resistance 辐射电阻除以传输电阻
2. Radiation resistance divided by total resistance 辐射电阻除以总电阻
3. Total resistance divided by radiation resistance 总电阻除以辐射电阻
4. Effective radiated power divided by transmitter output 有效辐射功率除以发射机输出

E9A10. Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna? 以下哪项可以提高地面安装的四分之一波长垂直天线的效率？

1. Installing a ground radial system 安装地面放射状系统
2. Isolating the coax shield from ground 将同轴电缆屏蔽与接地隔离
3. Shortening the radiating element 缩短辐射元件
4. All these choices are correct 所有这些选择都是正确的

E9A11. Which of the following determines ground losses for a ground-mounted vertical antenna operating on HF? 以下哪一项决定了在高频下工作的地面安装垂直天线的接地损耗？

1. The standing wave ratio 驻波比
2. Distance from the transmitter 与变送器的距离
3. Soil conductivity 土壤电导率
4. Take-off angle 起飞角度

E9A12. How much gain does an antenna have compared to a half-wavelength dipole if it has 6 dB gain over an isotropic radiator? 如果天线在各向同性辐射器上具有6dB的增益，那么与半波长偶极子相比，天线的增益是多少？

1. 3.85 dB 3.85分贝
2. 6.0 dB 6.0分贝
3. 8.15 dB 8.15分贝
4. 2.79 dB 2.79分贝

E9B01. What is the 3 dB beamwidth of the antenna radiation pattern shown in Figure E9-1? 图E9-1所示天线辐射方向图的3 dB波束宽度是多少？

1. 75 degrees 75度
2. 50 degrees 50度
3. 25 degrees 25度
4. 30 degrees 30度

E9B02. What is the front-to-back ratio of the antenna radiation pattern shown in Figure E9-1? 如图E9-1所示，天线辐射方向图的前后比是多少？

1. 36 dB 36分贝
2. 14 dB 14分贝
3. 24 dB 24分贝
4. 18 dB 18分贝

E9B03. What is the front-to-side ratio of the antenna radiation pattern shown in Figure E9-1? 如图E9-1所示，天线辐射方向图的正面与侧面之比是多少？

1. 12 dB 12分贝
2. 24 dB 24分贝
3. 18 dB 18分贝
4. 14 dB 14分贝

E9B04. What is the front-to-back ratio of the radiation pattern shown in Figure E9-2? 图E9-2所示的辐射图的前后比是多少？

1. 15 dB 15分贝
2. 28 dB 28分贝
3. 3 dB 3分贝
4. 38 dB 38分贝

E9B05. What type of antenna pattern is shown in Figure E9-2? 图E9-2中显示了哪种类型的天线方向图？

1. Elevation 高程
2. Azimuth 方位角
3. Near field 近场
4. Polarization 极化

E9B06. What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2? 图E9-2所示天线辐射方向图中峰值响应的仰角是多少？

1. 45 degrees 45度
2. 75 degrees 75度
3. 7.5 degrees 7.5度
4. 25 degrees 25度

E9B07. What is the difference in radiated power between a lossless antenna with gain and an isotropic radiator driven by the same power? 具有增益的无损天线和由相同功率驱动的各向同性辐射器之间的辐射功率差异是什么？

1. The power radiated from the directional antenna is increased by the gain of the antenna 定向天线辐射的功率增加了天线的增益
2. The power radiated from the directional antenna is stronger by its front-to-back ratio 定向天线辐射的功率因其前后比而更强
3. They are the same 他们是一样的
4. The power radiated from the isotropic radiator is 2.15 dB greater than that from the directional antenna 各向同性辐射器辐射的功率比定向天线辐射的功率大2.15 dB

E9B08. What is the far field of an antenna? 天线的远场是多少？

1. The region of the ionosphere where radiated power is not refracted 电离层中辐射功率没有折射的区域
2. The region where radiated power dissipates over a specified time period 辐射功率在指定时间段内耗散的区域
3. The region where radiated field strengths are constant 辐射场强恒定的区域
4. The region where the shape of the radiation pattern no longer varies with distance 辐射图案形状不再随距离变化的区域

E9B09. What type of analysis is commonly used for modeling antennas? 天线建模通常使用哪种类型的分析？

1. Graphical analysis 图形分析
2. Method of Moments 矩量法
3. Mutual impedance analysis 互阻抗分析
4. Calculus differentiation with respect to physical properties 关于物理性质的微积分微分

E9B10. What is the principle of a Method of Moments analysis? 矩量分析法的原理是什么？

1. A wire is modeled as a series of segments, each having a uniform value of current 导线被建模为一系列线段，每个线段都具有统一的电流值
2. A wire is modeled as a single sine-wave current generator 将导线建模为单个正弦波电流发生器
3. A wire is modeled as a single sine-wave voltage source 将导线建模为单个正弦波电压源
4. A wire is modeled as a series of segments, each having a distinct value of voltage across it 导线被建模为一系列线段，每条线段上都有不同的电压值

E9B11. What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength? 将天线模型中的线段数量减少到每半波长10个线段以下的缺点是什么？

1. Ground conductivity will not be accurately modeled 地面导电率将无法准确建模
2. The resulting design will favor radiation of harmonic energy 由此产生的设计将有利于谐波能量的辐射
3. The computed feed point impedance may be incorrect 计算的馈电点阻抗可能不正确
4. The antenna will become mechanically unstable 天线将变得机械不稳定

E9C01. What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase? 两个1/4波长的垂直天线间隔1/2波长并以180度异相馈电，会产生什么类型的辐射图？

1. Cardioid 心形
2. Omni-directional 全方位
3. A figure-eight broadside to the axis of the array 一个八字形宽边到阵列的轴
4. A figure-eight oriented along the axis of the array 沿阵列轴定向的图形8

E9C02. What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/4-wavelength apart and fed 90 degrees out of phase? 两个1/4波长的垂直天线间隔1/4波长并以90度异相馈电，会产生什么类型的辐射图？

1. Cardioid 心形
2. A figure-eight end-fire along the axis of the array 八字形末端沿阵列轴线开火
3. A figure-eight broadside to the axis of the array 一个八字形宽边到阵列的轴
4. Omni-directional 全方位

E9C03. What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase? 两个间隔1/2波长并同相馈电的1/4波长垂直天线产生了什么类型的辐射图？

1. Omni-directional 全方位
2. Cardioid 心形
3. A figure-eight broadside to the axis of the array 一个八字形宽边到阵列的轴
4. A figure-eight end-fire along the axis of the array 八字形末端沿阵列轴线开火

E9C04. What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased? 当导线长度增加时，未端接的长导线天线的辐射方向图会发生什么变化？

1. Fewer lobes form with the major lobes increasing closer to broadside to the wire 更少的裂片形成，主裂片在靠近金属丝的宽侧增加
2. Additional lobes form with major lobes increasingly aligned with the axis of the antenna 形成附加波瓣，主波瓣与天线轴线越来越对齐
3. The elevation angle increases, and the front-to-rear ratio decreases 仰角增大，前后比例减小
4. The elevation angle increases, while the front-to-rear ratio is unaffected 仰角增加，而前后比例不受影响

E9C05. What is the purpose of feeding an off-center-fed dipole (OCFD) between the center and one end instead of at the midpoint? 在中心和一端之间而不是在中点处馈电偏心馈电偶极子（OCFD）的目的是什么？

1. To create a similar feed point impedance on multiple bands 在多个频带上创建相似的馈电点阻抗
2. To suppress off-center lobes at higher frequencies 抑制较高频率下的偏心波瓣
3. To resonate the antenna across a wider range of frequencies 使天线在更宽的频率范围内谐振
4. To reduce common-mode current coupling on the feed line shield 减少馈线屏蔽上的共模电流耦合

E9C06. What is the effect of adding a terminating resistor to a rhombic or long-wire antenna? 在菱形或长导线天线上添加端接电阻器的效果如何？

1. It reflects the standing waves on the antenna elements back to the transmitter 它将天线元件上的驻波反射回发射器
2. It changes the radiation pattern from bidirectional to unidirectional 它将辐射模式从双向变为单向
3. It changes the radiation pattern from horizontal to vertical polarization 它将辐射方向图从水平偏振变为垂直偏振
4. It decreases the ground loss 它减少了地面损耗

E9C07. What is the approximate feed point impedance at the center of a two-wire half-wave folded dipole antenna? 双线半波折叠偶极天线中心的近似馈电点阻抗是多少？

1. 300 ohms 300欧姆
2. 72 ohms 72欧姆
3. 50 ohms 50欧姆
4. 450 ohms 450欧姆

E9C08. What is a folded dipole antenna? 什么是折叠偶极天线？

1. A dipole one-quarter wavelength long 四分之一波长长的偶极子
2. A center-fed dipole with the ends folded down 90 degrees at the midpoint of each side 中心馈电偶极子，两端在每侧中点向下折叠90度
3. A half-wave dipole with an additional parallel wire connecting its two ends 一个半波偶极子，两端连接一根额外的平行线
4. A dipole configured to provide forward gain 配置为提供正向增益的偶极子

E9C09. Which of the following describes a G5RV antenna? 以下哪项描述G5RV天线？

1. A wire antenna center-fed through a specific length of open-wire line connected to a balun and coaxial feed line 有线天线中心通过连接到巴伦和同轴馈线的特定长度的开路馈线馈电
2. A multi-band trap antenna 一种多频段陷波天线
3. A phased array antenna consisting of multiple loops 由多个环路组成的相控阵天线
4. A wide band dipole using shorted coaxial cable for the radiating elements and fed with a 4:1 balun 一种宽带偶极子，使用短路同轴电缆作为辐射元件，并配有4:1巴伦

E9C10. Which of the following describes a Zepp antenna? 以下哪项描述了Zepp天线？

1. A horizontal array capable of quickly changing the direction of maximum radiation by changing phasing lines 能够通过改变相位线快速改变最大辐射方向的水平阵列
2. An end-fed half-wavelength dipole 端馈半波长偶极子
3. An omni-directional antenna commonly used for satellite communications 一种常用于卫星通信的全向天线
4. A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines 能够通过改变相位线快速改变最大辐射方向的垂直阵列

E9C11. How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil? 安装在海水和土壤上的垂直极化天线的远场仰角模式是如何受到影响的？

1. Radiation at low angles decreases 低角度辐射降低
2. Additional lobes appear at higher elevation angles 额外的瓣叶出现在较高的仰角处
3. Separate elevation lobes will combine into a single lobe 单独的仰角波瓣将合并为一个波瓣
4. Radiation at low angles increases 低角度辐射增加

E9C12. Which of the following describes an extended double Zepp antenna? 以下哪项描述了扩展的双Zepp天线？

1. An end-fed full-wave dipole antenna 端馈全波偶极天线
2. A center-fed 1.5-wavelength dipole antenna 一种中心馈电的1.5波长偶极天线
3. A center-fed 1.25-wavelength dipole antenna 中心馈电1.25波长偶极天线
4. An end-fed 2-wavelength dipole antenna 端馈双波长偶极天线

E9C13. How does the radiation pattern of a horizontally polarized antenna vary with increasing height above ground? 水平极化天线的辐射方向图如何随着离地高度的增加而变化？

1. The takeoff angle of the lowest elevation lobe increases 最低仰角的起飞角增加
2. The takeoff angle of the lowest elevation lobe decreases 最低仰角的起飞角减小
3. The horizontal beamwidth increases 水平波束宽度增加
4. The horizontal beamwidth decreases 水平波束宽度减小

E9C14. How does the radiation pattern of a horizontally-polarized antenna mounted above a long slope compare with the same antenna mounted above flat ground? 安装在长斜坡上的水平极化天线的辐射方向图与安装在平地上的相同天线相比如何？

1. The main lobe takeoff angle increases in the downhill direction 主瓣起飞角沿下坡方向增大
2. The main lobe takeoff angle decreases in the downhill direction 主瓣起飞角沿下坡方向减小
3. The horizontal beamwidth decreases in the downhill direction 水平波束宽度在下坡方向上减小
4. The horizontal beamwidth increases in the uphill direction 水平波束宽度在上坡方向上增加

E9D01. How much does the gain of an ideal parabolic reflector antenna increase when the operating frequency is doubled? 当工作频率加倍时，理想抛物面反射器天线的增益增加了多少？

1. 2 dB 2分贝
2. 3 dB 3分贝
3. 4 dB 4分贝
4. 6 dB 6分贝

E9D02. How can two linearly polarized Yagi antennas be used to produce circular polarization? 如何使用两个线性极化的八木天线来产生圆极化？

1. Stack two Yagis to form an array with the respective elements in parallel planes fed 90 degrees out of phase 将两个Yagis堆叠在一起，形成一个阵列，其中各个元素位于平行平面中，相位相差90度
2. Stack two Yagis to form an array with the respective elements in parallel planes fed in phase 将两个Yagis堆叠起来，形成一个阵列，其中各个元素位于平行平面中，相位一致
3. Arrange two Yagis on the same axis and perpendicular to each other with the driven elements at the same point on the boom and fed 90 degrees out of phase 将两个Yagis布置在同一轴上，彼此垂直，从动元件位于动臂上的同一点，并异相进给90度
4. Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase 将两个Yagis彼此共线排列，驱动元件180度异相馈电

E9D03. What is the most efficient location for a loading coil on an electrically short whip? 电短鞭状物上负载线圈的最有效位置是什么？

1. Near the center of the vertical radiator 垂直散热器中心附近
2. As low as possible on the vertical radiator 在垂直散热器上尽可能低
3. At a voltage maximum 在最大电压下
4. At a voltage null 电压为零时

E9D04. Why should antenna loading coils have a high ratio of reactance to resistance? 为什么天线负载线圈应该具有高电抗与电阻之比？

1. To swamp out harmonics 淹没谐波
2. To lower the radiation angle 降低辐射角
3. To maximize efficiency 最大限度地提高效率
4. To minimize the Q 为了最小化Q

E9D05. Approximately how long is a Yagi’s driven element? 八木的驱动元素大约有多长？

1. 234 divided by frequency in MHz 234除以频率（MHz）
2. 1005 divided by frequency in MHz 1005除以频率（MHz）
3. 1/4 wavelength 1/4波长
4. 1/2 wavelength 1/2波长

E9D06. What happens to SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna? 当一个或多个负载线圈用于使电短路天线谐振时，SWR带宽会发生什么变化？

1. It is increased 它增加了
2. It is decreased 它减少了
3. It is unchanged if the loading coil is located at the feed point 如果加载线圈位于馈电点，则保持不变
4. It is unchanged if the loading coil is located at a voltage maximum point 如果负载线圈位于电压最大点，则其保持不变

E9D07. What is an advantage of top loading an electrically short HF vertical antenna? 顶部加载电短路HF垂直天线的优点是什么？

1. Lower Q 较低Q
2. Greater structural strength 更大的结构强度
3. Higher losses 更高的损失
4. Improved radiation efficiency 提高辐射效率

E9D08. What happens as the Q of an antenna increases? 当天线的Q值增加时会发生什么？

1. SWR bandwidth increases SWR带宽增加
2. SWR bandwidth decreases SWR带宽降低
3. Gain is reduced 增益降低
4. More common-mode current is present on the feed line 馈线上存在更多共模电流

E9D09. What is the function of a loading coil in an electrically short antenna? 短路天线中的负载线圈的功能是什么？

1. To increase the SWR bandwidth by increasing net reactance 通过增加净电抗来增加SWR带宽
2. To lower the losses 降低损失
3. To lower the Q 降低Q
4. To resonate the antenna by cancelling the capacitive reactance 通过消除容抗使天线谐振

E9D10. How does radiation resistance of a base-fed whip antenna change below its resonant frequency? 基馈鞭状天线的辐射电阻在低于其谐振频率时是如何变化的？

1. Radiation resistance increases 抗辐射能力增强
2. Radiation resistance decreases 抗辐射性降低
3. Radiation resistance becomes imaginary 辐射电阻变为虚值
4. Radiation resistance does not depend on frequency 抗辐射性不取决于频率

E9D11. Why do most two-element Yagis with normal spacing have a reflector instead of a director? 为什么大多数具有正常间距的二元亚吉斯都有反射器而不是指向矢？

1. Lower SWR SWR下限
2. Higher receiving directivity factor 更高的接收方向性因子
3. Greater front-to-side 从前面到侧面更大
4. Higher gain 更高的增益

E9D12. What is the purpose of making a Yagi’s parasitic elements either longer or shorter than resonance? 让八木的寄生元件比共振长或短的目的是什么？

1. Wind torque cancellation 风力扭矩取消
2. Mechanical balance 机械平衡
3. Control of phase shift 相移控制
4. Minimize losses 最大限度地减少损失

E9E01. Which matching system for Yagi antennas requires the driven element to be insulated from the boom? 八木天线的哪种匹配系统需要驱动元件与吊杆绝缘？

1. Gamma 伽马
2. Beta or hairpin Beta或发夹
3. Shunt-fed 并联馈电
4. T-match T-匹配

E9E02. What antenna matching system matches coaxial cable to an antenna by connecting the shield to the center of the antenna and the conductor a fraction of a wavelength to one side? 什么天线匹配系统通过将屏蔽连接到天线的中心，并将一小部分波长的导体连接到一侧来将同轴电缆与天线匹配？

1. Gamma match Gamma匹配
2. Delta match 德尔塔匹配
3. T-match T-匹配
4. Stub match Stub匹配

E9E03. What matching system uses a short length of transmission line connected in parallel with the feed line at or near the feed point? 什么匹配系统使用与馈电点或馈电点附近的馈线并联的短传输线？

1. Gamma match Gamma匹配
2. Delta match 德尔塔匹配
3. T-match T-匹配
4. Stub match Stub匹配

E9E04. What is the purpose of the series capacitor in a gamma match? 串联电容器在伽马匹配中的用途是什么？

1. To provide DC isolation between the feed line and the antenna 在馈线和天线之间提供直流隔离
2. To cancel unwanted inductive reactance 消除不需要的电感电抗
3. To provide a rejection notch that prevents the radiation of harmonics 提供抑制谐波辐射的抑制陷波
4. To transform the antenna impedance to a higher value 将天线阻抗转换为更高的值

E9E05. What Yagi driven element feed point impedance is required to use a beta or hairpin matching system? 使用β或发夹匹配系统需要什么八木驱动元件馈电点阻抗？

1. Capacitive (driven element electrically shorter than 1/2 wavelength) 电容式（驱动元件电短于1/2波长）
2. Inductive (driven element electrically longer than 1/2 wavelength) 电感式（驱动元件的电气长度超过1/2波长）
3. Purely resistive 纯电阻
4. Purely reactive 纯反应性

E9E06. Which of these transmission line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm feed point impedance to a 50-ohm transmission line? 这些传输线阻抗中的哪一个将适合于构建用于将100欧姆馈电点阻抗匹配到50欧姆传输线的四分之一波Q段？

1. 50 ohms 50欧姆
2. 62 ohms 62欧姆
3. 75 ohms 75欧姆
4. 90 ohms 90欧姆

E9E07. What parameter describes the interaction of a load and transmission line? 什么参数描述了负载和输电线路的相互作用？

1. Characteristic impedance 特性阻抗
2. Reflection coefficient 反射系数
3. Velocity factor 速度系数
4. Dielectric constant 介电常数

E9E08. What is a use for a Wilkinson divider? 威尔金森分配器有什么用？

1. To divide the operating frequency of a transmitter signal so it can be used on a lower frequency band 划分发射机信号的工作频率，使其可以用于较低的频带
2. To feed high-impedance antennas from a low-impedance source 从低阻抗源向高阻抗天线馈电
3. To divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance 在保持50欧姆输入阻抗的同时，在两个50欧姆负载之间平均分配功率
4. To divide the frequency of the input to a counter to increase its frequency range 对计数器的输入频率进行分频以增加其频率范围

E9E09. Which of the following is used to shunt feed a grounded tower at its base? 以下哪一项用于在接地塔的底部分流馈电？

1. Double-bazooka match 双火箭筒火柴
2. Beta or hairpin match Beta或发夹匹配
3. Gamma match Gamma匹配
4. All these choices are correct 所有这些选择都是正确的

E9E10. Which matching system places an inductance across the feed point of a vertical monopole antenna? 哪种匹配系统在垂直单极天线的馈电点上放置电感？

1. Gamma 伽马
2. Shunt-fed 并联馈电
3. Beta or hairpin Beta或发夹
4. T-match T-匹配

E9E11. What is the purpose of using multiple driven elements connected through phasing lines? 使用通过相位线连接的多个驱动元件的目的是什么？

1. To control the antenna’s radiation pattern 控制天线的辐射方向图
2. To prevent harmonic radiation from the transmitter 防止发射器产生谐波辐射
3. To allow single-band antennas to operate on other bands 允许单波段天线在其他波段工作
4. To create a low-angle radiation pattern 创建低角度辐射图案

E9F01. What is the velocity factor of a transmission line? 输电线路的速度系数是多少？

1. The ratio of its characteristic impedance to its termination impedance 其特性阻抗与终端阻抗之比
2. The ratio of its termination impedance to its characteristic impedance 其终端阻抗与其特性阻抗之比
3. The velocity of a wave in the transmission line multiplied by the velocity of light in a vacuum 波在传输线上的速度乘以真空中的光速
4. The velocity of a wave in the transmission line divided by the velocity of light in a vacuum 波在传输线上的速度除以真空中的光速

E9F02. Which of the following has the biggest effect on the velocity factor of a transmission line? 以下哪项对输电线路的速度系数影响最大？

1. The characteristic impedance 特性阻抗
2. The transmission line length 输电线路长度
3. The insulating dielectric material 绝缘电介质材料
4. The center conductor resistivity 中心导体电阻率

E9F03. Why is the electrical length of a coaxial cable longer than its physical length? 为什么同轴电缆的电气长度比其物理长度长？

1. Skin effect is less pronounced in the coaxial cable 趋肤效应在同轴电缆中不太明显
2. Skin effect is more pronounced in the coaxial cable 趋肤效应在同轴电缆中更为明显
3. Electromagnetic waves move faster in coaxial cable than in air 电磁波在同轴电缆中比在空气中传播得更快
4. Electromagnetic waves move more slowly in a coaxial cable than in air 电磁波在同轴电缆中的传播速度比在空气中慢

E9F04. What impedance does a 1/2-wavelength transmission line present to an RF generator when the line is shorted at the far end? 当线路在远端短路时，1/2波长传输线对射频发生器的阻抗是多少？

1. Very high impedance 非常高的阻抗
2. Very low impedance 非常低的阻抗
3. The same as the characteristic impedance of the line 与线路的特性阻抗相同
4. The same as the output impedance of the RF generator 与射频发生器的输出阻抗相同

E9F05. What is microstrip? 什么是微带？

1. Special shielding material designed for microwave frequencies 专为微波频率设计的特殊屏蔽材料
2. Miniature coax used for low power applications 用于低功率应用的微型同轴电缆
3. Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits 安装在印刷电路板上的短同轴电缆，以最大限度地减少微波电路之间的时间延迟
4. Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies 接地平面上方的精密印刷电路导体，在微波频率下提供恒定阻抗互连

E9F06. What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz? 在14.10 MHz下，电气长度为1/2波长的空气绝缘平行导体传输线的近似物理长度是多少？

1. 7.0 meters 7.0米
2. 8.5 meters 8.5米
3. 10.6 meters 10.6米
4. 13.3 meters 13.3米

E9F07. How does parallel conductor transmission line compare to coaxial cable with a plastic dielectric? 平行导体传输线与塑料电介质的同轴电缆相比如何？

1. Lower loss 更低的损失
2. Higher SWR SWR更高
3. Smaller reflection coefficient 反射系数较小
4. Lower velocity factor 低速系数

E9F08. Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric coaxial cable, assuming all other parameters are the same? 假设所有其他参数相同，以下哪一项是泡沫介质同轴电缆和固体介质同轴电缆之间的显著区别？

1. Foam dielectric coaxial cable has lower safe maximum operating voltage 泡沫介质同轴电缆具有较低的安全最大工作电压
2. Foam dielectric coaxial cable has lower loss per unit of length 泡沫介质同轴电缆单位长度损耗较低
3. Foam dielectric coaxial cable has higher velocity factor 泡沫介质同轴电缆具有更高的速度系数
4. All these choices are correct 所有这些选择都是正确的

E9F09. What impedance does a 1/4-wavelength transmission line present to an RF generator when the line is shorted at the far end? 当线路远端短路时，1/4波长传输线对射频发生器的阻抗是多少？

1. Very high impedance 非常高的阻抗
2. Very low impedance 非常低的阻抗
3. The same as the characteristic impedance of the transmission line 与传输线的特性阻抗相同
4. The same as the generator output impedance 与发电机输出阻抗相同

E9F10. What impedance does a 1/8-wavelength transmission line present to an RF generator when the line is shorted at the far end? 当线路远端短路时，1/8波长传输线对射频发生器的阻抗是多少？

1. A capacitive reactance 电容电抗
2. The same as the characteristic impedance of the line 与线路的特性阻抗相同
3. An inductive reactance 电感电抗
4. Zero 零

E9F11. What impedance does a 1/8-wavelength transmission line present to an RF generator when the line is open at the far end? 当线路远端开路时，1/8波长传输线对射频发生器的阻抗是多少？

1. The same as the characteristic impedance of the line 与线路的特性阻抗相同
2. An inductive reactance 电感电抗
3. A capacitive reactance 电容电抗
4. Infinite 极大的

E9F12. What impedance does a 1/4-wavelength transmission line present to an RF generator when the line is open at the far end? 当线路远端开路时，1/4波长传输线对射频发生器的阻抗是多少？

1. The same as the characteristic impedance of the line 与线路的特性阻抗相同
2. The same as the input impedance to the generator 与发电机的输入阻抗相同
3. Very high impedance 非常高的阻抗
4. Very low impedance 非常低的阻抗

E9G01. Which of the following can be calculated using a Smith chart? 以下哪项可以使用史密斯圆图进行计算？

1. Impedance along transmission lines 沿传输线的阻抗
2. Radiation resistance 抗辐射性
3. Antenna radiation pattern 天线辐射方向图
4. Radio propagation 无线电传播

E9G02. What type of coordinate system is used in a Smith chart? 史密斯圆图使用哪种类型的坐标系？

1. Voltage circles and current arcs 电压圆和电流弧
2. Resistance circles and reactance arcs 电阻圆和电抗弧
3. Voltage chords and current chords 电压弦和电流弦
4. Resistance lines and reactance chords 电阻线和电抗弦

E9G03. Which of the following is often determined using a Smith chart? 以下哪一项经常使用史密斯圆图来确定？

1. Beam headings and radiation patterns 波束指向和辐射方向图
2. Satellite azimuth and elevation bearings 卫星方位角和仰角
3. Impedance and SWR values in transmission lines 传输线中的阻抗和SWR值
4. Point-to-point propagation reliability as a function of frequency 作为频率函数的点对点传播可靠性

E9G04. What are the two families of circles and arcs that make up a Smith chart? 构成史密斯圆图的圆和弧的两个族是什么？

1. Inductance and capacitance 电感和电容
2. Reactance and voltage 电抗和电压
3. Resistance and reactance 电阻和电抗
4. Voltage and impedance 电压和阻抗

E9G05. Which of the following is a common use for a Smith chart? 以下哪项是史密斯圆图的常用项？

1. Determine the length and position of an impedance matching stub 确定阻抗匹配短截线的长度和位置
2. Determine the impedance of a transmission line, given the physical dimensions 在给定物理尺寸的情况下，确定传输线的阻抗
3. Determine the gain of an antenna given the physical and electrical parameters 在给定物理和电气参数的情况下，确定天线的增益
4. Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials 在给定速度系数和导体材料的情况下，确定输电线路的损耗/100英尺

E9G06. On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate? 在图E9-3所示的史密斯圆图上，电抗弧终止的大外圈的名称是什么？

1. Prime axis 素轴
2. Reactance axis 电抗轴
3. Impedance axis 阻抗轴
4. Polar axis 极轴

E9G07. On the Smith chart shown in Figure E9-3, what is the only straight line shown? 在图E9-3所示的史密斯圆图上，唯一显示的直线是什么？

1. The reactance axis 电抗轴
2. The current axis 当前轴
3. The voltage axis 电压轴
4. The resistance axis 阻力轴

E9G08. How is a Smith chart normalized? 史密斯圆图是如何归一化的？

1. Reassign the reactance axis with resistance values 用电阻值重新分配电抗轴
2. Reassign the resistance axis with reactance values 用电抗值重新分配电阻轴
3. Reassign the prime center’s impedance value 重新指定基本中心的阻抗值
4. Reassign the prime center to the reactance axis 将质心重新分配到电抗轴

E9G09. What third family of circles is often added to a Smith chart during the process of designing impedance matching networks? 在设计阻抗匹配网络的过程中，史密斯圆图中经常添加哪些第三族圆？

1. Constant-SWR circles 恒定SWR圆
2. Transmission line length circles 输电线路长度圆
3. Coaxial-length circles 同轴长度圆
4. Radiation-pattern circles 辐射图案圆

E9G10. What do the arcs on a Smith chart represent? 史密斯圆图上的弧代表什么？

1. Frequency 频率
2. SWR 短波无线电
3. Points with constant resistance 具有恒定电阻的点
4. Points with constant reactance 具有恒定电抗的点

E9G11. In what units are the wavelength scales on a Smith chart calibrated? 史密斯圆图上的波长刻度是以什么单位校准的？

1. In fractions of transmission line electrical frequency 在传输线电气频率的分数中
2. In fractions of transmission line electrical wavelength 传输线电波长的分数
3. In fractions of antenna electrical wavelength 天线电波长的分数
4. In fractions of antenna electrical frequency 天线电气频率的分数

E9H01. When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency? 在构建饮料天线时，设计中应包括以下哪些因素，以在所需频率下实现良好性能？

1. Its overall length must not exceed 1/4 wavelength 其总长度不得超过1/4波长
2. It must be mounted more than 1 wavelength above ground 它必须安装在离地1个波长以上
3. It should be configured as a four-sided loop 应将其配置为四边环
4. It should be at least one wavelength long 它应该至少有一个波长长

E9H02. Which is generally true for 160- and 80-meter receiving antennas? 对于160米和80米的接收天线，这通常是正确的？

1. Atmospheric noise is so high that directivity is much more important than losses 大气噪声如此之高，指向性比损耗重要得多
2. They must be erected at least 1/2 wavelength above the ground to attain good directivity 它们必须架设在离地至少1/2波长的地方，以获得良好的指向性
3. Low loss coax transmission line is essential for good performance 低损耗同轴传输线对良好性能至关重要
4. All these choices are correct 所有这些选择都是正确的

E9H03. What is receiving directivity factor (RDF)? 什么是接收方向性因子（RDF）？

1. Forward gain compared to the gain in the reverse direction 正向增益与反向增益的比较
2. Relative directivity compared to isotropic 与各向同性相比的相对方向性
3. Relative directivity compared to a dipole 与偶极子相比的相对方向性
4. Peak antenna gain compared to average gain over the hemisphere around and above the antenna 天线周围和上方半球上的峰值天线增益与平均增益的比较

E9H04. What is the purpose of placing an electrostatic shield around a small-loop direction-finding antenna? 在小型环形测向天线周围放置静电屏蔽的目的是什么？

1. It adds capacitive loading, increasing the bandwidth of the antenna 它增加了电容负载，增加了天线的带宽
2. It eliminates unbalanced capacitive coupling to the antenna’s surroundings, improving the depth of its nulls 它消除了与天线周围环境的不平衡电容耦合，提高了零点的深度
3. It eliminates tracking errors caused by strong out-of-band signals 它消除了由强带外信号引起的跟踪误差
4. It increases signal strength by providing a better match to the feed line 它通过提供与馈线更好的匹配来提高信号强度

E9H05. What challenge is presented by a small wire-loop antenna for direction finding? 小型线环天线在测向方面面临什么挑战？

1. It has a bidirectional null pattern 它具有双向null模式
2. It does not have a clearly defined null 它没有明确定义的null
3. It is practical for use only on VHF and higher bands 它仅适用于VHF和更高波段
4. All these choices are correct 所有这些选择都是正确的

E9H06. What indicates the correct value of terminating resistance for a Beverage antenna? 什么指示饮料天线的端接电阻的正确值？

1. Maximum feed point DC resistance at the center of the desired frequency range 所需频率范围中心的最大馈电点直流电阻
2. Minimum low-angle front-to-back ratio at the design frequency 设计频率下的最小低角度前后比
3. Maximum DC current in the terminating resistor 终端电阻器中的最大直流电流
4. Minimum variation in SWR over the desired frequency range SWR在所需频率范围内的最小变化

E9H07. What is the function of a Beverage antenna’s termination resistor? 饮料天线的终端电阻器的功能是什么？

1. Increase the front-to-side ratio 增加前侧比
2. Absorb signals from the reverse direction 吸收反向信号
3. Decrease SWR bandwidth 降低SWR带宽
4. Eliminate harmonic reception 消除谐波接收

E9H08. What is the function of a sense antenna? 感应天线的功能是什么？

1. It modifies the pattern of a DF antenna to provide a null in only one direction 它修改测向天线的方向图以仅在一个方向上提供零位
2. It increases the sensitivity of a DF antenna array 它提高了测向天线阵列的灵敏度
3. It allows DF antennas to receive signals at different vertical angles 它允许测向天线接收不同垂直角度的信号
4. It provides diversity reception that cancels multipath signals 它提供分集接收，可消除多径信号

E9H09. What type of radiation pattern is created by a single-turn, terminated loop such as a pennant antenna? 单匝端接环路（如三角旗天线）会产生什么类型的辐射方向图？

1. Cardioid 心形
2. Bidirectional 双向的
3. Omnidirectional 全向
4. Hyperbolic 双曲线

E9H10. How can the output voltage of a multiple-turn receiving loop antenna be increased? 如何提高多匝接收环形天线的输出电压？

1. By reducing the permeability of the loop shield 通过降低环形屏蔽的磁导率
2. By utilizing high impedance wire for the coupling loop 通过将高阻抗导线用于耦合回路
3. By increasing the number of turns and/or the area enclosed by the loop 通过增加匝数和/或环路包围的面积
4. All these choices are correct 所有这些选择都是正确的

E9H11. What feature of a cardioid pattern antenna makes it useful for direction-finding antennas? 心形天线的什么特性使其对测向天线有用？

1. A very sharp peak 一座非常陡峭的山峰
2. A single null 单个null
3. Broadband response 宽带响应
4. High radiation angle 高辐射角

E0A01. What is the primary function of an external earth connection or ground rod? 外部接地连接或接地棒的主要功能是什么？

1. Prevent static build up on power lines 防止电力线上的静电积聚
2. Lightning charge dissipation 雷电电荷耗散
3. Reduce RF current flow between pieces of equipment 减少设备之间的射频电流
4. Protect breaker panel from power surges 保护断路器面板免受电涌的影响

E0A02. When evaluating RF exposure levels from your station at a neighbor’s home, what must you do? 当在邻居家评估你的电台的射频暴露水平时，你必须做什么？

1. Ensure signals from your station are less than the controlled maximum permissible exposure (MPE) limits 确保来自工作站的信号小于控制的最大允许曝光（MPE）限制
2. Ensure signals from your station are less than the uncontrolled maximum permissible exposure (MPE) limits 确保来自工作站的信号小于不受控制的最大允许曝光（MPE）限制
3. Ensure signals from your station are less than the controlled maximum permissible emission (MPE) limits 确保来自站点的信号小于受控最大允许排放（MPE）限值
4. Ensure signals from your station are less than the uncontrolled maximum permissible emission (MPE) limits 确保来自站点的信号小于不受控制的最大允许排放（MPE）限值

E0A03. Over what range of frequencies are the FCC human body RF exposure limits most restrictive? FCC人体射频暴露限制在什么频率范围内最严格？

1. 300 kHz - 3 MHz 300千赫-3兆赫
2. 3 - 30 MHz 3-30兆赫
3. 30 - 300 MHz 30-300兆赫
4. 300 - 3000 MHz 300-3000兆赫

E0A04. When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations? 在评估多个变送器同时运行的现场时，哪些变送器的操作员和许可证持有者负责缓解过度暴露的情况？

1. Each transmitter that produces 20 percent or more of its MPE limit in areas where the total MPE limit is exceeded 在超过总MPE限制的区域内产生其MPE限制20%或更多的每个发射器
2. Each transmitter operating with a duty cycle greater than 25 percent 工作循环大于25%的每个变送器
3. Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded 在超过总MPE限值的区域内产生5%或更多MPE限的每个变送器
4. Each transmitter operating with a duty cycle greater than 50 percent 工作循环大于50%的每个变送器

E0A05. What hazard is created by operating at microwave frequencies? 在微波频率下工作会产生什么危害？

1. Microwaves are ionizing radiation 微波是电离辐射
2. The high gain antennas commonly used can result in high exposure levels 通常使用的高增益天线会导致高曝光水平
3. Microwaves are in the frequency range where wave velocity is higher 微波在波速度较高的频率范围内
4. The extremely high frequency energy can damage the joints of antenna structures 极高的频率能量会损坏天线结构的接头

E0A06. Why are there separate electric (E) and magnetic (H) MPE limits at frequencies below 300 MHz? 为什么在低于300 MHz的频率下有单独的电（E）和磁（H）MPE限制？

1. The body reacts to electromagnetic radiation from both the E and H fields 身体对来自E场和H场的电磁辐射作出反应
2. Ground reflections and scattering cause the field strength to vary with location 地面反射和散射导致场强随位置变化
3. E field and H field radiation intensity peaks can occur at different locations E场和H场辐射强度峰值可以出现在不同的位置
4. All these choices are correct 所有这些选择都是正确的

E0A07. What is meant by “100% tie-off” regarding tower safety? 什么是关于塔架安全的“100%捆绑”？

1. All loose ropes and guys secured to a fixed structure 所有松散的绳索和固定在固定结构上的绳索
2. At least one lanyard attached to the tower at all times 始终至少有一根系索连接到塔架上
3. All tools secured to the climber’s harness 所有固定在登山者安全带上的工具
4. All circuit breakers feeding power to the tower must be tied closed with tape, cable, or ties 所有向风塔供电的断路器必须用胶带、电缆或扎带捆扎闭合

E0A08. What does SAR measure? SAR测量什么？

1. Signal attenuation ratio 信号衰减率
2. Signal amplification rating 信号放大额定值
3. The rate at which RF energy is absorbed by the body 身体吸收射频能量的速率
4. The rate of RF energy reflected from stationary terrain 从静止地形反射的射频能量的速率

E0A09. Which of the following types of equipment are exempt from RF exposure evaluations? 以下哪种类型的设备免于进行射频暴露评估？

1. Transceivers with less than 7 watts of RF output 射频输出小于7瓦的收发器
2. Antennas that radiate only in the near field 只在近场辐射的天线
3. Hand-held transceivers sold before May 3, 2021 2021年5月3日前售出的手持式收发器
4. Dish antennas less than one meter in diameter 直径小于一米的碟形天线

E0A10. When must an RF exposure evaluation be performed on an amateur station operating on 80 meters? 什么时候必须对在80米上运行的业余电台进行射频暴露评估？

1. An evaluation must always be performed 必须始终进行评估
2. When the ERP of the station is less than 10 watts 当电站的ERP小于10瓦时
3. When the station’s operating mode is CW 当电台的工作模式为CW时
4. When the output power from the transmitter is less than 100 watts 当变送器的输出功率小于100瓦时

E0A11. To what should lanyards be attached while climbing? 攀爬时应将系索系在什么上？

1. Antenna mast 天线杆
2. Guy brackets 拉线支架
3. Tower rungs 塔架梯级
4. Tower legs 塔腿

E0A12. Where should a shock-absorbing lanyard be attached to a tower when working above ground? 在地面上工作时，应将减震系索连接到塔架的何处？

1. Above the climber’s head level 高于攀登者的头部
2. To the belt of the fall-arrest harness 至防坠落安全带的皮带
3. Even with the climber's waist 即使是攀登者的腰部
4. To the next lowest set of guys 给下一个最底层的人