大学MOOC 通信电路与系统(杭州电子科技大学)1462436163 最新慕课完整章节测试答案
Chapter 5 Angle Modulation and Demodulation
文章目录
6月16日课前练习
1、单选题：
In the slope detector, FM signal is converted to ( ) .
选项：
A: FM-PM signal
B: AM-FM signal
C: PM-FM signal
D: AM-PM signal
答案: 【 AM-FM signal】
2、单选题：
In order to ensure linear frequency discrimination, at least the bandwidth of frequency discriminator must be greater than ( ) .
选项：
A: 2 times the modulation frequency of input FM signal
B: 2 times the maximum frequency shift of input FM signal
C: 2 times the bandwidth of input FM signal
D: 2 times the carrier frequency of input FM signal
答案: 【 2 times the maximum frequency shift of input FM signal】
3、判断题：
In the phase discriminator, FM signal is converted to AM-FM signal .
选项：
A: 正确
B: 错误
答案: 【 错误】
6月2日课前练习
1、单选题：
Angle modulation includes FM and（ ）.
选项：
A: AM
B: FM
C: PM
D: DSB
答案: 【 PM】
2、单选题：
The maximum frequency shift of FM signal only depends on ( ).
选项：
A: The amplitude of carrier signal
B: The amplitude of modulating signal
C: The frequency of modulating signal
D: The frequency of carrier signal
答案: 【 The amplitude of modulating signal】
3、判断题：
FM has better anti-interference capability than AM.
选项：
A: 正确
B: 错误
答案: 【 正确】
4、判断题：
In the PM signal, the frequency changes linearly with the modulation signal.
选项：
A: 正确
B: 错误
答案: 【 错误】
5、判断题：
The frequency of modulation signal has little effect to the bandwidth of FM.
选项：
A: 正确
B: 错误
答案: 【 错误】
6、判断题：
Theoretically, both FM and PM signals have infinite spectrum structure.
选项：
A: 正确
B: 错误
答案: 【 正确】
7、判断题：
The power of FM and PM signals both are only related to the power of carrier wave.
选项：
A: 正确
B: 错误
答案: 【 正确】
8、判断题：
Direct frequency modulation is a way to control the oscillator’s frequency.
选项：
A: 正确
B: 错误
答案: 【 正确】
9、判断题：
The larger the maximum frequency shift, the better the FM circuit performance.
选项：
A: 正确
B: 错误
答案: 【 正确】
6月9日课前练习
1、单选题：
The major disadvantage of direct FM is ( )
选项：
A: narrow frequency shift
B: bad frequency stability
C: low output amplitude
D: low output frequency
答案: 【 bad frequency stability】
2、判断题：
PM can be used in the FM generating circuit.
选项：
A: 正确
B: 错误
答案: 【 正确】
3、判断题：
The key part of indirect FM circuit is the phase modulation.
选项：
A: 正确
B: 错误
答案: 【 正确】
4、判断题：
The frequency stability of indirect FM circuit is good, the frequency shift is narrow.
选项：
A: 正确
B: 错误
答案: 【 正确】
5、判断题：
The FM circuit with crystal oscillator has high central frequency stability, as well as wide frequency shift.
选项：
A: 正确
B: 错误
答案: 【 错误】
6、判断题：
Frequency discrimination bandwidth is related to the bandwidth of input FM signal.
选项：
A: 正确
B: 错误
答案: 【 正确】
7、判断题：
Discriminating characteristics of the slope detector is concerned with Q of the LC tuned circuit.
选项：
A: 正确
B: 错误
答案: 【 正确】
8、判断题：
The larger trans-conductance gd of the frequency detector, the better the frequency discrimination performance.
选项：
A: 正确
B: 错误
答案: 【 正确】
9、判断题：
The larger bandwidth of the frequency detector, the better the frequency discrimination performance.
选项：
A: 正确
B: 错误
答案: 【 正确】
10、填空题：
In the direct FM circuit with varactor diode as total capacitance, when n= ( ), the circuit realize linear frequency modulation.
答案: 【 2】
Chapter1 Introduction to Basic Knowledge of Communication Electronics Circuits
3月10日课前练习
1、单选题：
What is the core of the transmitter？
选项：
A: Mixer
B: Modulator
C: Oscillator
D: Amplifier
答案: 【 Modulator】
2、单选题：
Which of the following circuits is not part of super heterodyne receiver?
选项：
A: Local oscillator
B: Mixer
C: Intermediate frequency amplifier
D: Modulator
答案: 【 Modulator】
3、单选题：
FM radio signal belongs to which wave type?
选项：
A: VLF
B: VHF
C: UHF
D: HF
答案: 【 VHF】
4、单选题：
When the resistive load increases, the selectivity of LC parallel resonant circuit will be improved, but（ ）will be decreased.
选项：
A: Quality factor Q
B: Resonant frequency f0
C: Rectangular coefficient K0.1
D: Pass band B0.7
答案: 【 Pass band B0.7】
5、判断题：
In the wireless communication system , the transmitter and receiver are both have oscillator circuits.
选项：
A: 正确
B: 错误
答案: 【 正确】
6、判断题：
The frequency of High frequency si