Digital Signal Processing Laboratory Viva Questions - Part 4

Q.1-
a) Periodic with period 4
b) Periodic with period 8
c) Periodic with period 16
d) Not periodic




Q.2- find the convolution between sequences x(n)=u(n+1)-u(n+4)-δ(n-5) and
         h(n)=[u(n+2)-u(n+3)].(3-|n|)

    a) {1,-3,6,8,9,8,5,1,-2,-2,-1}
                  ↑
    b) {1,3,6,8,9,8,5,1,-2,-2,-1}
                    ↑
    c) {1,3,6,8,9,8,5,1,-2,-2,-1}
                 ↑
    d) {1,3,6,8,9,8,5,1,-2,-2,-1}
                       ↑
    e) None of the above

Q.3- What are the limits for full overlap in convolution of two given sequences      
          x(n)={1,-3,6,8,9,8,5,1,-2}, h(n)={1,2,3,4,5,6}
                                 ↑                                                 ↑
a) -5 to 8
b) 1 to 14
c) 0 to 13
d) 0 to 3

Q.4- Consider the following statements:

A) All memory-less systems are causal systems.

B) Two systems S1 and S2 are connected in parallel, both S1 and S2 are stable,      will the parallel connection always be stable.

C) All memoryless systems are shift-invariant
 
True statements are:
a) A, B, C
b) A, C
c) A, B
d) B, C

Q.5- If x(n) = 0 for n < 0, and the odd part is  find x(n) given that x(0) = 1;

a)
b)
c)
d)


Q.6- Consider the interconnection of three linear shift-invariant systems shown in    the figure below.

                    
If h1(n) = u(n-2), h2(n) = nu(n) and h3(n) =  δ(n-3), find the unit sample response of the overall system.


a) Y(n) = u(n-4)+0.5(n-2)(n-1)u(n-2)
b) Y(n) = u(n+4)+0.5(n-2)(n-1)u(n-2)
c) Y(n) = u(n-4)+0.5(n-2)(n-1)u(n+2)
d) Y(n) = u(n-4)+2(n-2)(n-1)u(n-2)


Q.7- Consider the linear shift-invariant system described by the first-order linear constant coefficient difference equation:     
     
                               y(n) = ay(n-1)+x(n)
           
Determine the conditions (if any) for which this system is stable.



a)
b)
c)
d) Given data is not sufficient

Q.8- determine the range of values of a and b for which LTI system with impulse response h(n) is stable.

                    

a)
b)
c)
d) None of these





Q.9-   A system with input x(n) and output y(n) is given as:
 
                          
The system is

a) Linear, stable and invertible
b)  Non-linear, stable and non-invertible
c) Linear, unstable and invertible
d) Linear, stable and non-invertible


Q.10- A causal LTI system is described by the difference equation
 
             

The system is stable only if

a)
b)
c) ,any value of  b
d) , any value of a

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