FCC G4B - 业余无线电实践与电台操作

#G4B01🔗

What item of test equipment contains horizontal and vertical channel amplifiers?

哪项测试设备包含水平和垂直通道放大器？

An ohmmeter

欧姆表

A signal generator

信号发生器

An ammeter

电流表

An oscilloscope

示波器

✓ 正确答案

#G4B02🔗

Which of the following is an advantage of an oscilloscope versus a digital voltmeter?

以下哪项是示波器与数字电压表相比的优势？

An oscilloscope uses less power

示波器消耗更少的电量

Complex impedances can be easily measured

可以轻松测量复数阻抗

Greater precision

更高的精度

Complex waveforms can be measured

可测量复杂波形

✓ 正确答案

#G4B03🔗

Which of the following is the best instrument to use for checking the keying waveform of a CW transmitter?

以下哪种仪器最适合用于检查 CW 发射机的键控波形？

An oscilloscope

示波器

✓ 正确答案

A field strength meter

场强计

A sidetone monitor

侧音监听器

A wavemeter

波长计

#G4B04🔗

What signal source is connected to the vertical input of an oscilloscope when checking the RF envelope pattern of a transmitted signal?

检查传输信号的射频包络模式时，什么信号源连接到示波器的垂直输入？

The local oscillator of the transmitter

发射机的本地振荡器

An external RF oscillator

外部射频振荡器

The transmitter balanced mixer output

发射机平衡混频器输出

The attenuated RF output of the transmitter

发射器的衰减射频输出

✓ 正确答案

#G4B05🔗

Why do voltmeters have high input impedance?

为什么电压表输入阻抗高？

It improves the frequency response

它改善了频率响应

It allows for higher voltages to be safely measured

它允许安全测量更高的电压

It improves the resolution of the readings

它提高了读数的分辨率

It decreases the loading on circuits being measured

它减少了被测电路的负载

✓ 正确答案

#G4B06🔗

What is an advantage of a digital multimeter as compared to an analog multimeter?

与模拟万用表相比，数字万用表有什么优势？

Better for measuring computer circuits

更适合测量计算机电路

Less prone to overload

不易发生过载

Higher precision

精度更高

✓ 正确答案

Faster response

响应速度更快

#G4B07🔗

What signals are used to conduct a two-tone test?

使用什么信号进行双音测试？

Two audio signals of the same frequency shifted 90 degrees

两个相同频率的音频信号偏移 90 度

Two non- harmonically related audio signals

两个非谐波相关的音频信号

✓ 正确答案

Two swept frequency tones

两个扫频音

Two audio frequency range square wave signals of equal amplitude

两个等幅音频范围方波信号

#G4B08🔗

What transmitter performance parameter does a two-tone test analyze?

双音测试分析哪些发射机性能参数？

Linearity

线性度

✓ 正确答案

Percentage of suppression of the carrier and undesired sideband for SSB

SSB 的载波和不需要的边带的抑制百分比

Percentage of frequency modulation

调频百分比

Percentage of carrier phase shift

载波相移百分比

#G4B09🔗

When is an analog multimeter preferred to a digital multimeter?

什么时候模拟万用表优于数字万用表？

When testing logic circuits

测试逻辑电路时

When high precision is desired

当需要高精度时

When measuring the frequency of an oscillator

测量振荡器的频率时

When adjusting circuits for maximum or minimum values

当调整电路的最大值或最小值时

✓ 正确答案

#G4B10🔗

Which of the following can be determined with a directional wattmeter?

使用定向瓦特计可以测定以下哪项？

Standing wave ratio

驻波比

✓ 正确答案

Antenna front-to-back ratio

天线前后比

RF interference

射频干扰

Radio wave propagation

无线电波传播

#G4B11🔗

Which of the following must be connected to an antenna analyzer when it is being used for SWR measurements?

使用天线分析仪进行 SWR 测量时，必须连接以下哪项？

Receiver

接收器

Transmitter

发射机

Antenna and feed line

天线和馈线

✓ 正确答案

All these choices are correct

所有这些选项都是正确的

#G4B12🔗

What effect can strong signals from nearby transmitters have on an antenna analyzer?

来自附近发射器的强信号会对天线分析仪产生什么影响？

Desensitization which can cause intermodulation products which interfere with impedance readings

减敏可能会导致互调产物干扰阻抗读数

Received power that interferes with SWR readings

干扰 SWR 读数的接收功率

✓ 正确答案

Generation of harmonics which interfere with frequency readings

产生干扰频率读数的谐波

All these choices are correct

所有这些选项都是正确的

#G4B13🔗

Which of the following can be measured with an antenna analyzer?

以下哪项可以使用天线分析仪进行测量？

Front-to-back ratio of an antenna

天线前后比

Power output from a transmitter

发射机的功率输出

Impedance of coaxial cable

同轴电缆的阻抗

✓ 正确答案

Gain of a directional antenna

定向天线的增益

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FCC G4B - 业余无线电实践与电台操作

小节 G4B：业余无线电实践与电台操作