Digital Signal Processing Laboratory Viva Questions - Part 5

Q.1-   Determine the DTFT for the given signal and choose correct option.
a)
b)
c)
d) None of the above




Q.2- A real signal x(n) with DTFT X(ejw) has following property:
1. x(n) = 0   for n > 0
2. x(0) > 0
3. Im {X(ejw) = sin(w) – sin(2w)}
4.
The signal x(n) is
a) 2δ(n) - δ(n+1) - δ(n+3)
b) δ(n) + δ(n+1) - δ(n+3)
c) δ(n) +δ(n+1) - δ(n+2)
d) 2δ(n) - δ(n+1) - δ(n+2)
Statement for Q. 3-4
From the following signals choose the signals, whose DTFT satisy the condition given in the question.
A. x(n)= δ(n-1)- δ(n+1)
B. x(n)= {2, -1, -1, 0, 1, 0, 1, 0, -1, -1, 2}
                                        ↑
               C.
                D. x(n)= δ(n-1)- δ(n+2)
Q.3-
    
a) A and B
b) B and C
c) A and C
d) Only A

Q.4-
a) A and B
b) B and C
c) Only C
d) Only A


Q.5- The numeric value of
a)
b)
c)
d)

Q.6- A real signal x(n) has DTFT X(ejw). Which one of the following is correct?
a) Magnitude of the X(ejw) has even symmetry while phase of  X(ejw) has odd symmetry.
b) Magnitude of the X(ejw) has odd symmetry while phase of  X(ejw) has even symmetry.
c) Both magnitude and phase of  X(ejw) have even symmetry.
d) Both magnitude and phase of  X(ejw) have odd symmetry.
Q.7. A discrete time signal x(n) has Fourier transform X(ejw).
     Match List-1(signal) with List-II (Fourier Transform) and select the correct answer using the code given below the lists:
         List-1                                         List-2
A.  x(-n)                                        1.  X*(e-jw)
B.  nx(n)                                        2. X(e-jw)
C.  x*(n)                                         3. e-jwX(ejw)
D.  x(n-1)                                       4.
Codes:
          A   B   C    D
a) 1    3    2    4
b) 2    4    1    3
c) 1    4    2    3
d) 2    3    1    4

Q.8- If x(n)↔X(ejw) be the Fourier transform pair. The Fourier transfer of the signal x(5n-3) in the terms of X(ejw) is given as
a)
b)
c)
d)

Q.9- DTFT of
                                      
a) sin((N+1/2)ω)/sin(ω/2)
b) sin(N+ω/2)/sin(Nω/2)
c) sin((N+1/2)ω)/sin(Nω/2)
d) sin((Nω)/sin(ω/2)
e) None of the above



Q.10- find DTFT of two sided sequence  x(n)=(1/4)^‌n‌
a) 15/(15-8 cos ω )
b) 15/(17-8 cos ω )
c) 15/(17-8 sin ω )
d) 15/(15-8 sin ω )
e) None of the above




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