Digital Signal Processing Laboratory Viva Questions - Part 1

Theory_Questions:

Q.1-find the DFT of  x(n)={1,1,1,1,1,1,1,1}
a) {8,-1,0,0,-1,0,0,0}
b) {8,0,2,0,0,0,0,0}
c)  {8,0,0,0,0,0,0,0}
d)  {8,1,0,0,1,0,0,0}
e) None of the above



Q.2 - circular convolution of two sequences x(n)={1,2,3,1} y(n)={4,3,2,1}
a) {15,16,18,21}
b) {15,21,21,18}
c) {15,18,21,16}
d) {15,16,21,18}
e) None of the above

Q.3 - IDFT of sequence is  X(k)={8,0,-4j,0,0,0,4j,0}
a) {1,2,1,0,1,2,-1,0}
b) {1,2,-1,0,1,2,1,0}
c) {1,2,1,0,1,2,1,0}
d) {1,2,-1,0,1,2,-1,0}
e) None of the above

Q.4 - if x(n)={4, 3, 2, 1} then x(8-n)mod4
a) {4, 3, 2, 1}
b) {3, 4, 2, 1}
c) {2, 3, 4, 1}
d) {4, 1, 2, 3}
e) None of the above

Q. 5 - If x1(n) is real and symmetric w.r.t n=2 and x2(n) is real and symmetrical w.r.t n=1.
                                
                                  y(n) = x1(n-2) + x2(n-1)  .

          if DTFT of y(n) is Y( ejw), then Phase angle of Y( ejw) is
a) 0
b)
c) W
d) 2w





Q.6 - If impulse response h(n) of a system is cascade of 2 LTI systems having impulse responses of h1(n) and h2(n). if h(n) ≠ 0 for  -2 ≤  n ≤  2 then which of them are always true

a) both h1(n) and h2(n) can't non causal at a time
b)  both h1(n) and h2(n) can't anti causal at a time
c) both are non causal
d) None of the above

Q.7- If x(n)  ≠ 0 for 0  ≤  n ≤ 3   and x(n) = 0 for others. X(k) is obtained by taking 5 point DFT of x(n)  the the values of X(-2), X(-50),X(50)  are

a) X(2) , X(2), X(2)
b) X(1), X(2), X(2)
c) X(3), X(0), X(0)
d) None of the above

Q.8 - DTFT of x*(-n) is:
 
a) X(e-jw)
b) X(ejw)
c) X*( e-jw)
d) X*( ejw)

Q.9 – The response of a linear, time-invariant discrete-time system to a unit step input u(n) is the impulse . The system response to a ramp input nu(n) would be
a) u(n)
b) u(n-1)
c) n
d) None of the above

Q.10-   
              Which one of the following systems is inverse of the system given above?

a) x(n) = y(n)-y(n-1)
b) x(n) = y(n)
c) x(n) = y(n+4)
d) x(n) = ny(n)


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