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?‍‎‍
选项:
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
答案: 【 x[n] = cos(5π/7 – 5n/9) 

2、单选题:

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

​选项:
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]
答案: 【 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 _​
选项:
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, …
答案: 【 1, 0, -1, 0, 1, 0, -1, 0, …

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_‎‎‎
选项:
A: 80Hz
B: 160Hz
C: 320Hz
D: 640Hz
答案: 【 320Hz

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________​‎​
选项:
A: 10010000,  01000011000100000000000000000000
B: 00010000,  01000011000100000000000000000000
C: 10010000, 11000011000100000000000000000000
D: 00010000, 11000011000100000000000000000000
答案: 【 10010000,  01000011000100000000000000000000

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
选项:
A: 44dB
B: 50dB
C: 56dB
D: 62dB
答案: 【 50dB

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 ‍‏‍
选项:
A:
B:
C:
D:
答案: 【 

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 ‏‌‏‌‏
选项:
A:
B:
C:
D:
答案: 【 

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] = _____‏‍‏
选项:
A: 0
B: 4
C: -4
D: 1
答案: 【 4

2、单选题:
​Which of the following equation is right ?​
选项:
A:
B:
C:
D:
答案: 【 

3、多选题:
‎Consider the continuous-time signal xa(t) = 4sin(20πt),which of the following frequencies won’t cause‍‎ frequency spectrum overlap _______‍
选项:
A: 10Hz
B: 20Hz
C: 40Hz
D: 80Hz
答案: 【 40Hz;
80Hz

4、判断题:
‍The  sampling frequency is only determined by the highest frequency component of the signal.​‍​
选项:
A: 正确
B: 错误
答案: 【 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_______‌‌‌
答案: 【 interpolation

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?‎
选项:
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.
答案: 【 The continuous signal in time domain and the nonperiodic signal in frequency domain.

The Definition of DTFT-1 Quiz

1、单选题:

‍选项:
A:
B:
C: None
D:
答案: 【 

2、单选题:

‏选项:
A:
B:
C:
D:
答案: 【 

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:

‏选项:
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.
答案: 【 The sequence is not absolutely summable, but the square summable.

2、单选题:

‏选项:
A:
B:
C:
D:
答案: 【 

The Definition of DTFT-3 Quiz

1、单选题:

‏选项:
A: 3142π
B: 2484π
C: 3098π
D: 2986π
答案: 【 3142π

2、单选题:

‏选项:
A:
B:
C:
D:
答案: 【 

The Importance of Signal Analysis in Transform Domain Quiz

1、多选题:
‌Why do we do transformation domain analysis of signals?‎‌‎
选项:
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.
答案: 【 richer analytical methods.;
more prominent signal characteristics.;
the analysis of the problem can be simplified.

Topic3-1 Test

1、单选题:

‏选项:
A:
B:
C:
D: Undetermined
答案: 【 

2、单选题:

‌选项:
A:
B:
C:
D:
答案: 【 

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

4、多选题:

‍选项:
A: It is absolute summable.
B: It is square summable.
C: Its DFT exists.
D: It has finite energy.
答案: 【 It is absolute summable.;
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?‍
选项:
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.
答案: 【 Spectrum of DTFT can be obtain by extending the continuous-time signal periodically by sampling frequency.;
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

‏选项:
A: Linearity theorem
B: Time-shifting theorem
C: Differentiation-in-frequency theorem
D: Convolution theorem
答案: 【 Linearity theorem;
Time-shifting theorem

7、判断题:
‌If a sequence x[n] is even, its DTFT must be conjugate symmetric.​
选项:
A: 正确
B: 错误
答案: 【 错误

Topic 3-2 z-transform

Inverse z transform-1 Quiz

1、单选题:

‎选项:
A:
B:
C:
D:
答案: 【 

2、单选题:

‌选项:
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)
答案: 【 x[n]={7,-2.7,1.17,-0.567,0.2997,...}(n≥0)

Inverse z transform-2 Quiz

1、单选题:

‎选项:
A:
B:
C:
D:
答案: 【 

Topic 3-2 Test

1、单选题:

‏选项:
A:
B:
C:
D:
答案: 【 

2、单选题:
‏Which of the following statement is false about the inverse ZT?​
选项:
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.
答案: 【 The contour integral definition of inverse ZT can be solved only by Residue Method or contour integration.

3、单选题:

‌选项:
A:

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