FCC G8A - 信号与发射模式

#G8A01🔗

How is direct binary FSK modulation generated?

直接二进制 FSK 调制是如何生成的？

By keying an FM transmitter with a sub-audible tone

通过使用亚音频键控 FM 发射机

By changing an oscillator ’s frequency directly with a digital control signal

通过使用数字控制信号直接改变振荡器的频率

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By using a transceiver’s computer data interface protocol to change frequencies

通过使用收发器的计算机数据接口协议来改变频率

By reconfiguring the CW keying input to act as a tone generator

通过重新配置 CW 键控输入以充当音频发生器

#G8A02🔗

What is the name of the process that changes the phase angle of an RF signal to convey information?

改变射频信号相位角以传递信息的过程的名称是什么？

Phase convolution

相位卷积

Phase modulation

相位调制

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Phase transformation

相变

Phase inversion

相转化

#G8A03🔗

What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?

改变射频波瞬时频率以传递信息的过程的名称是什么？

Frequency convolution

频率卷积

Frequency transformation

变频

Frequency conversion

变频

Frequency modulation

调频

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#G8A04🔗

What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?

连接到发射器射频放大器级的电抗调制器会产生什么发射？

Multiplex modulation

多路调制

Phase modulation

相位调制

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Amplitude modulation

调幅

Pulse modulation

脉冲调制

#G8A05🔗

What type of modulation varies the instantaneous power level of the RF signal?

什么类型的调制会改变射频信号的瞬时功率电平？

Power modulation

功率调制

Phase modulation

相位调制

Frequency modulation

调频

Amplitude modulation

调幅

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#G8A06🔗

Which of the following is characteristic of QPSK31?

QPSK31 具有以下哪些特性？

It is sideband sensitive

它是边带敏感的

Its encoding provides error correction

它的编码提供纠错功能

Its bandwidth is approximately the same as BPSK31

其带宽与BPSK31大致相同

All these choices are correct

所有这些选项都是正确的

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#G8A07🔗

Which of the following phone emissions uses the narrowest bandwidth?

以下哪种电话发射使用的带宽最窄？

Single sideband

单边带

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Vestigial sideband

残留边带

Phase modulation

相位调制

Frequency modulation

调频

#G8A08🔗

Which of the following is an effect of overmodulation?

以下哪项是过调制的影响？

Insufficient audio

音频不足

Insufficient bandwidth

带宽不足

Frequency drift

频率漂移

Excessive bandwidth

带宽过多

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#G8A09🔗

What type of modulation is used by FT8?

FT8 使用什么类型的调制？

8- tone frequency shift keying

8 音移频键控

✓ 正确答案

Vestigial sideband

残留边带

Amplitude compressed AM

幅度压缩 AM

8-bit direct sequence spread spectrum

8位直接序列扩频

#G8A10🔗

What is meant by the term “flat-topping,” when referring to an amplitude-modulated phone signal?

当提到调幅电话信号时，术语“平顶”是什么意思？

Signal distortion caused by insufficient collector current

集电极电流不足导致信号失真

The transmitter’s automatic level control (ALC) is properly adjusted

发射机的自动电平控制（ALC）已正确调整

Signal distortion caused by excessive drive or speech levels

驱动或语音电平过高导致信号失真

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The transmitter’s carrier is properly suppressed

发射机的载波被适当抑制

#G8A11🔗

What is the modulation envelope of an AM signal?

AM 信号的调制包络是多少？

The waveform created by connecting the peak values of the modulated signal

通过连接调制信号的峰值创建的波形

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The carrier frequency that contains the signal

包含信号的载波频率

Spurious signals that envelop nearby frequencies

包围附近频率的杂散信号

The bandwidth of the modulated signal

调制信号的带宽

#G8A12🔗

What is QPSK modulation?

什么是QPSK调制？

Modulation using quasi-parallel to serial conversion to reduce bandwidth

使用准并行到串行转换进行调制以减少带宽

Modulation using quadra-pole sideband keying to generate spread spectrum signals

使用四极边带键控生成扩频信号进行调制

Modulation using Fast Fourier Transforms to generate frequencies at the first, second, third, and fourth harmonics of the carrier frequency to improve noise immunity

使用快速傅立叶变换进行调制，生成载波频率的第一、第二、第三和第四谐波频率，以提高抗噪能力

Modulation in which digital data is transmitted using 0 -, 90 -, 180 - and 270 - degrees phase shift to represent pairs of bits

使用 0、90、180 和 270 度相移来传输数字数据以表示位对的调制

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#G8A13🔗

What is a link budget?

什么是链接预算？

The financial costs associated with operating a radio link

与运营无线电链路相关的财务成本

The sum of antenna gains minus system losses

天线增益减去系统损耗之和

The sum of transmit power and antenna gains minus system losses as seen at the receiver

发射功率和天线增益之和减去接收器处看到的系统损耗

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The difference between transmit power and receiver sensitivity

发射功率和接收灵敏度的区别

#G8A14🔗

What is link margin?

什么是链接边距？

The opposite of fade margin

与淡入淡出边缘相反

The difference between received power level and minimum required signal level at the input to the receiver

接收器输入端接收到的功率电平与所需的最低信号电平之间的差异

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Transmit power minus receiver sensitivity

发射功率减去接收灵敏度

Receiver sensitivity plus 3 dB

接收器灵敏度加 3 dB

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FCC G8A - 信号与发射模式

小节 G8A：信号与发射模式