# Digital Signal Processing(University of Electronic Science and Technology of China)1458252163 中国大学MOOC答案100分完整版

Digital Signal Processing(University of Electronic Science and Technology of China)1458252163 中国大学MOOC答案100分完整版

## Topic 2 Digital Processing of Continuous Signals-1

### Discrete Time Signals Quiz

1、单选题：
‎Which of the following discrete sequences is not a periodic sequence？‍‎‍

A: x[n]=e-j0.4πn
B: x[n]= 3sin(1.5πn) – 4cos(1.4πn + 0.45π)
C: x[n] = cos(5π/7 – 5n/9)
D: x[n]= 0.5sin(2.4πn)ej0.4πn

2、单选题：

Determine the expression for the y[n] of the system shown in the following figure

A: y[n] = p0x[n]–p1x[n-1]–d1y[n-1]
B: y[n] = p0x[n]+p1x[n-1]–d1y[n-1]
C: y[n] = p0x[n]–p1x[n+1]–d1y[n+1]
D: y[n] = p0x[n]+p1x[n+1]–d1y[n+1]

### Sampling the Continuous Signals Quiz

1、单选题：
A analog sinusoidal signal xa(t) = cos(6πt)u(t)，is sampled at sampling frequency of 12Hz.Its discrete-time sequence is _​

A: 1，0，1，0，1，0，1，0，…
B: 1, -1, 1, -1, 1, -1, 1, -1, …
C: 1, 0, -1, 0, 1, 0, -1, 0, …
D: 1, 1, -1, -1, 1, 1, -1, -1, …

2、单选题：
(1) Given that continuous-time signal xa(t)=4sin(20πt) – 5cos(40πt) + 3sin(120πt) +  2cos(176πt), to sample the signal, its minimum sampling frequency  satisfying Nyquist rate among the following is_‎‎‎

A: 80Hz
B: 160Hz
C: 320Hz
D: 640Hz

## Topic 2 Digital Processing of Continuous Signals-2

### Finite Word Length in ADC Quiz

1、单选题：
‎Floating point 144.0 is represented by an 8-bit binary fixed point as________  ,and the binary floating point representation based on the IEEE 32-bit standard is________​‎​

A: 10010000,  01000011000100000000000000000000
B: 00010000,  01000011000100000000000000000000
C: 10010000, 11000011000100000000000000000000
D: 00010000, 11000011000100000000000000000000

2、单选题：
‎During ADC conversion, a sinusoidal signal with amplitude being 1 is input and the ADC operates at full range. When the quantization word length b = 8bits(one symbol bit and seven data bits), the SNR of the quantization process is approximately‏

A: 44dB
B: 50dB
C: 56dB
D: 62dB

### Reconstruction of Continuous Signals Quiz

1、单选题：
‏Suppose a Digital-to-Analog Conversion system with the sampling frequency being 1kHz. If the original signal can be fully recovered , the frequency response of the reconstruction filter Hr (j Ω) of the DAC is ‍‏‍

A:
B:
C:
D:

2、单选题：
‌‏ Suppose a Digital-to-Analog Conversion system with the sampling frequency being 1kHz. If the original signal can be fully recovered , the impulse response hr(t) of the reconstruction filter  of the DAC is ‏‌‏‌‏

A:
B:
C:
D:

### Topic 2 Test

1、单选题：
‍A continuous-time signal xa(t) = 4sin(20πt) is sampled at frequency f=40Hz，determine the value of sample x[1] = _____‏‍‏

A: 0
B: 4
C: -4
D: 1

2、单选题：
​Which of the following equation is right ？​

A:
B:
C:
D:

3、多选题：
‎Consider the continuous-time signal xa(t) = 4sin(20πt)，which of the following frequencies won’t cause‍‎ frequency spectrum overlap _______‍

A: 10Hz
B: 20Hz
C: 40Hz
D: 80Hz

80Hz

4、判断题：
‍The  sampling frequency is only determined by the highest frequency component of the signal.​‍​

A: 正确
B: 错误

5、填空题：
‌In the time domain， the procedure of restoring the original continuous-time signal from discrete sample values is called_______‌‌‌

## Topic 3-1 DTFT

### DTFT From CTFT Quiz

1、单选题：
‎What is the relationship between the time domain and the frequency domain of CTFT?‎

A: The continuous periodic signal in time domain and the continuous periodic signal in frequency domain.
B: The continuous signal in time domain and the nonperiodic signal in frequency domain.
C: The discrete signal in time domain and the periodic signal in frequency domain.
D: The periodic signal in time domain and the discrete signal in frequency domain.

### The Definition of DTFT-1 Quiz

1、单选题：

A:
B:
C: None
D:

2、单选题：

A:
B:
C:
D:

3、填空题：

Without computing the DTFT,determine which of the following DTFTs have an inverse transfer that is an odd sequence_

(directly write the letter of each choice without any blanks or other Symbols, such as ‘abc’)

‌答案:  bc

### The Definition of DTFT-2 Quiz

1、单选题：

A: The sequence is absolutely summable, and square summable.
B: The sequence is absolutely summable, but not square summable.
C: The sequence is not absolutely summable, but the square summable.
D: The sequence is neither absolutely summable nor square summable.

2、单选题：

A:
B:
C:
D:

1、单选题：

A: 3142π
B: 2484π
C: 3098π
D: 2986π

2、单选题：

A:
B:
C:
D:

### The Importance of Signal Analysis in Transform Domain Quiz

1、多选题：
‌Why do we do transformation domain analysis of signals？‎‌‎

A: richer analytical methods.
B: more prominent signal characteristics.
C: more complex mathematical tools can be used.
D: the analysis of the problem can be simplified.

more prominent signal characteristics.;
the analysis of the problem can be simplified.

### Topic3-1 Test

1、单选题：

A:
B:
C:
D: Undetermined

2、单选题：

A:
B:
C:
D:

3、单选题：
‎Which of the following is true about the magnitude spectrum and phase spectrum of  DTFT？‎

A: DTFT of discrete-time signal can be divided into magnitude spectrum and phase spectrum, and both are complex function of ω.
B: The magnitude of a discrete-time signal is an even function of ω，while the phase spectrum of that is an odd function of ω.
C: If the phase spectrum of a discrete-time signal always has a discontinuous amplitude at πand -π with a jump of 2π, it is possible to be brought by phase wrap.
D: Magnitude spectrum and phase spectrum is the only form of DTFT of discrete-time signal.

4、多选题：

A: It is absolute summable.
B: It is square summable.
C: Its DFT exists.
D: It has finite energy.

It is square summable.;
Its DFT exists.;
It has finite energy.

5、多选题：
‎Which of the following is false about the relationship between DTFT and CTFT？‍

A: DTFT is only different from CTFT on the continuity and discreteness of time domain signal and the units in frequency domain. And DTFT can be transformed CTFT.
B: DTFT is always used to represent the spectrum of discrete-time signals，while CTFT is used to represent the spectrum of continuous-time signals.
C: Spectrum of DTFT can be obtain by extending the continuous-time signal periodically by sampling frequency.
D: DTFT and CTFT are totally different concept for discrete-time signal and continuous-time signal and cannot be connected.

DTFT and CTFT are totally different concept for discrete-time signal and continuous-time signal and cannot be connected.

6、多选题：

During the solution of DTFT as follows, which propertie are used

A: Linearity theorem
B: Time-shifting theorem
C: Differentiation-in-frequency theorem
D: Convolution theorem

Time-shifting theorem

7、判断题：
‌If a sequence x[n] is even, its DTFT must be conjugate symmetric.​

A: 正确
B: 错误

## Topic 3-2 z-transform

### Inverse z transform-1 Quiz

1、单选题：

A:
B:
C:
D:

2、单选题：

A: x[n]={7,3.6,1,0.9,0.18,…}(n≥0）
B: x[n]={7,3.6,-1,-0.9,-0.18,…}(n≥0）
C: x[n]={7,-2.7,1.17,-0.567,0.2997,…}(n≥0）
D: x[n]={7,-2.7,-1.17,0.567,-0.2997,…}(n≥0）

1、单选题：

A:
B:
C:
D:

### Topic 3-2 Test

1、单选题：

A:
B:
C:
D:

2、单选题：
‏Which of the following statement is false about the inverse ZT？​

A: The contour integral definition of inverse ZT can be deduced by inverse DTFT.
B: The contour integral definition of inverse ZT can be solved by Residue Method.
C: The contour integral definition of inverse ZT can be solved only by Residue Method or contour integration.
D: In the contour integral definition of inverse ZT，the contour C is a counterclockwise closed line in the ROC of z-transform.

3、单选题：

A: