Digital Signal Processing(Nanjing University of Posts and Telecommunications)mooc慕课答案2026年版满分测试WYC

对应课程:点击查看
起止时间:2021-03-08到2021-06-21
更新状态:已完结

1st Week： Unit 1 Introduction Unit Test for Unit 1

1、 If you want to digitize the speech signal for subsequent processing, the speech signal must be passed through:

A:anti-aliasing analog filter
B:D / A conversion
C:digital filter
D:A / D conversion
答案: anti-aliasing analog filter;
A / D conversion

2、 The digital signal is a discrete-time signal with discrete-valued amplitudes.

A:正确
B:错误
答案: 正确

2nd Week： Unit 2 Discrete-Time Signals in the Time Domain Unit Test for Unit 2

1、

A:5
B:10
C:
D:10/3
答案: 10

2、 Express as a linear combination of delayed unit sample sequences.

A:
B:
C:
D:
答案:

3、

A:
B:
C:
D:
答案:

4、 The length of the sequence obtained by linear convolution of length-M and length-N signals is

A:M + N
B:M + N -1
C:M + N +1
D:M * N
答案: M + N -1

5、

A:
B:
C:
D:
答案:

6、 Regarding the unit step sequence, the correct descriptions are

A:finite length sequence
B:causal sequence
C:infinite length sequence
D:right-sided sequence
答案: causal sequence;
infinite length sequence;
right-sided sequence

3rd Week： Unit 3 Discrete-Time Signals in the Frequency Domain Unit Test for Unit 3

1、

A:
B:
C:
D:
答案:

2、 For a discrete time sequence x[n], its DTFT must satisfy

A:
B:
C:
D:
答案:

3、

A:
B:
C:
D:
答案:

4、 Let denote the DTFT of the sequence then

A:0
B:-3
C:-5
D:uncertain
答案: -3

5、 Let denote the DTFT of the sequencethen

A:3
B:11
C:31
D:uncertain
答案: 31

6、 The DTFT of discrete time signal h[n] is then h[n] =

A:
B:
C:
D:
答案:

7、

A:正确
B:错误
答案: 错误

8、 The sequence x[n] has the same magnitude spectrum as its delayed sequence x[n-5].

A:正确
B:错误
答案: 正确

4th Week： Unit 4 Sampling and Recovery of Analog Signal Unit Test for Unit 4

1、 When sampling a continuous-time signal with a maximum frequency , to satisfy the Nyquist criterion of the sampling theorem, the range of the sampling interval T is

A:
B:
C:
D:
答案:

2、 Sampling two continuous-time sinusoidal signals with frequencies of and at the sampling frequency , if the two sequences obtained after sampling are equal, they need to meet

A:
B:
C:
D:No requirements for and
答案:

3、 Consider the continuous-time signal , is in units of seconds, and the discrete-time sequence is obtained after sampling, then the sampling frequency is

A:4000 Hz
B:1/8000 Hz
C:8000 Hz
D:2000 Hz
答案: 8000 Hz

4、 A continuous-time signal xa(t) is composed of a linear combination of sinusoidal signals of frequencies 300Hz, 500Hz, 1.2kHz, 2.15kHz and 3.5 kHz. The signal xa(t) is sampled at a 3 kHz rate, and the sampled sequence is then passed through an ideal lowpass filter with a cutoff frequency of 900 Hz, generating a continuous-time signal ya(t). What are the frequency components present in the reconstructed signal ya(t)?

A:300 Hz
B:850 Hz
C:1200 Hz
D:500 Hz
答案: 300 Hz;
850 Hz;
500 Hz

5、 The cut-off frequency of the reconstruction filter used to recover the analog signal is the sampling angular frequency.

A:正确
B:错误
答案: 错误

6、 Anti-aliasing filtering is only required before sampling an analog signal of unlimited bandwidth.

A:正确
B:错误
答案: 错误

5th Week： Unit 5 z-Transform Unit Test for Unit 5

1、 The region of convergence of z-transform of the sequence must not include:

A:zero