Digital Signal Processing Laboratory Viva Questions - Part 8

Q.1- A linear phase channel with phase delay T_p and group delay T_g must have

1. T_p = T_g = constant
2. T_p ∝ f and T_g ∝ f
3. T_p = constant and T_g ∝ f
4. T_p ∝ f and T_g = constant

Q.2- A signal is the input to a LTI system having frequency response H(e^jw). If the output of the system Ax(n - n_o), then the most general form of will be

1. –n_ow_o + β for any arbitrary real β
2. –n_ow_o + 2πk for any arbitrary integer k
3. n_ow_o + 2πk for any arbitrary integer k
4. –n_ow_oφ

Q.3- A system transfer function H(z) has impulse response h(n) defined as h(2) = 1, h(3) = -1 and h(k) = 0 otherwise. Consider the following statement

S1: H(z) is a low-pass filter

S2: H(z) is an FIR filter

Which of the following is correct?

1. Only S2 is true
2. Both S1 and S2 are true
3. Both S1 and S2 are true, and S2 is a reason for S1
4. Both S1 and S2 are true, S2 is not a reason for S1

Q.4- The transfer function of a system is given by

The system is

1. Minimum phase
2. Maximum phase
3. Mixed phase
4. None of the above

Q.5- The minimum number of delay elements required realizing a digital filter with the transfer function

1. 2
2. 3
3. 4
4. 5

Q.6- If a practically realizable digital filter allowing DC signal, but it is giving zero output for two frequencies (0<w<π). Then What will be the impulse response h(n) for that filter (i) {1/2,0,0,0,-1/2}, starting sample is h(0) (ii){1/2,0,0,0,1/2},starting sample is h(0) (iii){1/2,0,0,0,1/2},starting sample is h(2) (iv) {1/2,0,0,0,1/2}, starting sample is h(-2).

1. Only
2. (ii) only
3. (ii) and (iii)
4. (ii) and (iv)
5. (ii),(iii) and (iv)

Q.7- What is the maximum delay faced by the input x(t) for the best possible filter (less hardware needed for such filter) in the above problem. If maximum frequency component of x(t) is 1KHz and it is sampled at Nyquist rate.

1. 0.5 msec
2. 1 msec
3. 2 msec
4. 4 msec

Q.8- If H1(Z)=H(1/Z), and if H1(Z) is practically realizable High pass filter then

(i) H(-Z) is practically realizable high pass filter

(ii) H(-Z) is practically realizable low pass filter

Then which one is true

1. (i)Only
2. (ii) only
3. any one
4. None of the above

Q.9- (i) we can realize H1()=cos(w/2) practically by DSP techniques

(ii) we can realize H2()=cos(w/2). Practically by DSP techniques

Then which one is true

1. (i) only
2. (ii) only
3. Both (i) and (ii)
4. None of the above

Q.10- (i) If < 0 for 0<w< and >0 for <w<π , then is band stop filter

(ii) If > 0 for 0<w< and <0 for <w<π , then is band stop filter

(iii) If = k. for 0<w<π. Where k is a non zero constant, then is an all pass filter

Then which one is true

1. Only (i)
2. Only (ii)
3. Only (iii)
4. (i) and (iii)
5. (ii) and (iii)

Ans. Key:

1. a
2. b
3. a
4. c
5. b
6. c
7. c
8. d
9. d
10. a