Chapter 0 Back ground and preview

第零章单元测验

1、单选题:

‎选项:
A: a continuous rectangular pulses
B: a periodic sequence of rectangular pulses
C: a continuous sinusoidal signal
D: a periodic  sinusoidal signal
答案: 【 a periodic sequence of rectangular pulses

2、单选题:
‌The reverse of modulation is          .‏
选项:
A: encoding
B: demodulation
C: decoding
D: modulator
答案: 【 demodulation

3、单选题:
‏A common problem with electromagnetic wave propagation via sky wave in thehigh fequency (HF) range is          . ​
选项:
A: Wide transmission bandwidth
B: signal multipath
C: Linear time-varying channel
D: Broad-area coverage
答案: 【 signal multipath

4、多选题:
​Two primary resources employed in communication systems are              and          .       ‏
选项:
A:  power
B: bandwidth  
C: frequency
D: source of Information
答案: 【  power;
bandwidth  

5、多选题:
‍The three commonly used method of  multiplexing are         ,           and          .‍
选项:
A: FDM
B: TDM
C: CDM
D: FDMA
答案: 【 FDM;
TDM;
CDM

6、多选题:

‌选项:
A: transmitter
B: channel
C: receiver
D: source of imformation
答案: 【 transmitter;
channel;
receiver

7、多选题:

‍选项:
A: coaxial cable
B: telephone channel
C: universal Serial Bus
D: optical fiber
答案: 【 coaxial cable;
telephone channel;
optical fiber

8、多选题:

‍选项:
A: wireless broadcast channel
B: underwater acoustic channel
C:  satellite channel
D:  mobile radio channel
答案: 【 wireless broadcast channel;
 satellite channel;
 mobile radio channel

9、判断题:

‎选项:
A: 正确
B: 错误
答案: 【 错误

10、判断题:

‎选项:
A: 正确
B: 错误
答案: 【 正确

11、判断题:

‍选项:
A: 正确
B: 错误
答案: 【 正确

12、判断题:

‏选项:
A: 正确
B: 错误
答案: 【 错误

13、判断题:

​选项:
A: 正确
B: 错误
答案: 【 错误

14、判断题:

‏选项:
A: 正确
B: 错误
答案: 【 错误

15、判断题:

‍选项:
A: 正确
B: 错误
答案: 【 错误

16、判断题:

‏选项:
A: 正确
B: 错误
答案: 【 正确

17、判断题:

‏选项:
A: 正确
B: 错误
答案: 【 错误

18、填空题:

‏答案: 【 transmitter, channel, receiver

19、填空题:

​答案: 【 broadcasting, point-to-point communication

20、填空题:

‏答案: 【 transmitted power, channel bandwidth

21、填空题:

‎答案: 【 a sinusoidal wave

22、填空题:

​答案: 【 a periodic sequence of rectangular pulses

23、填空题:

‌答案: 【 the average signal power, the average noise power

24、填空题:

​答案: 【 band-limited

Chapter 1 Random processes

第一章单元测验-1

1、单选题:
‏This random process X (t) =cos(2πfct). the frequencies can be 100, 200, . . . , 600 Hz,then: ​
选项:
A: The possible values of X (0.001) could be cos(0.2π), cos(0.4π), . . . , cos(l .2π),and each has a probability 1/6.
B: The possible values of X (0.001) could be cos(0.1π), cos(0.2π), . . . , cos(0.6π), and each has a probability 1/6.
C: The possible values of X (0.001) could be cos(0.2π), cos(0.4π), . . . , cos(l .2π)
D: The possible values of X (0.001) could be cos(0.1π), cos(0.2π), . . . , cos(0.6π)
答案: 【 The possible values of X (0.001) could be cos(0.2π), cos(0.4π), . . . , cos(l .2π)

2、单选题:

‎选项:
A:
B:
C:
D:
答案: 【 

3、多选题:
Which one of the following functions can be the autocorrelation function of a random process?‌‌‌
选项:
A:
B:
C:
D:
答案: 【 ;
;

4、判断题:

‌选项:
A: 正确
B: 错误
答案: 【 错误

5、判断题:

​选项:
A: 正确
B: 错误
答案: 【 正确

6、判断题:

‏选项:
A: 正确
B: 错误
答案: 【 错误

第一章测试

1、多选题:
Considering the properties of the autocorrelation function Rx(τ) of a random process X(t).  ‌‎‌
选项:
A:
B:

C:
D:
答案: 【 
;

2、多选题:
‏Considering the properties of the sine wave plus narrowband noise. ‍
选项:
A: If the narrowband noise is Gaussian, the in-phase and quadrature components are jointly Gaussian.
B: Both the in-phase and quadrature component have the same variance.  
C: Both the in-phase and quadrature component have the same mean.  
D: The envelope and phase components are statistically independent.
答案: 【 If the narrowband noise is Gaussian, the in-phase and quadrature components are jointly Gaussian.;
Both the in-phase and quadrature component have the same variance.  

3、多选题:

‍选项:
A: The mean of Y is 0.
B:
C:
D: Y is also Gaussian
答案: 【 The mean of Y is 0.;
;
;
Y is also Gaussian

4、多选题:

‍选项:
A:
B:
C: The power in X(t) is 4W.
D: The power in X(t) is 8W.
答案: 【 ;
The

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