# Discrete Time System Analysis MCQ’s

This set of Digital Signal Processing Multiple Choice Questions & Answers (MCQs) focuses on “Discrete Time Systems Analysis”.

1. Determine the impulse response for the cascade of two LTI systems having impulse responses h_{1}(n)=(12)2 u(n) and h_{2}(n)=(14)2 u(n).

a) (12)n[2−(12)n], n<0

b) (12)n[2−(12)n], n>0

c) (12)n[2+(12)n], n<0

d) (12)n[2+(12)n], n>0

2. x(n)*δ(n-n_{0})=?

a) x(n+n_{0})

b) x(n-n_{0})

c) x(-n-n_{0})

d) x(-n+n_{0})

3. Resolve the sequence into a sum of weighted impulse sequences.

a) 2δ(n)+4δ(n-1)+3δ(n-3)

b) 2δ(n+1)+4δ(n)+3δ(n-2)

c) 2δ(n)+4δ(n-1)+3δ(n-2)

d) None of the mentioned

4. Determine the output y(n) of a LTI system with impulse response h(n)=a^{n}u(n), |a|<1with the input sequence x(n)=u(n).

a) 1−an+11−a

b) 1−an−11−a

c) 1+an+11+a

d) None of the mentioned

5. What is the order of the four operations that are needed to be done on h(k) in order to convolute x(k) and h(k)?

Step-1:Folding

Step-2:Multiplication with x(k)

Step-3:Shifting

Step-4:Summation

a) 1-2-3-4

b) 1-2-4-3

c) 2-1-3-4

d) 1-3-2-4

6. Is the system with impulse response h(n)=2^{n}u(n-1) stable.

a) True

b) False

7. x(n)*[h_{1}(n)+h_{2}(n)]=x(n)*h_{1}(n)+x(n)*h_{2}(n).

a) True

b) False

8. The impulse response of a LTI system is h(n)={1,1,1}. What is the response of the signal to the input x(n)={1,2,3}?

a) {1,3,6,3,1}

b) {1,2,3,2,1}

c) {1,3,6,5,3}

d) {1,1,1,0,0}

9. An LTI system is said to be causal if and only if?

a) Impulse response is non-zero for positive values of n

b) Impulse response is zero for positive values of n

c) Impulse response is non-zero for negative values of n

d) Impulse response is zero for negative values of n

10. The formula y(n)=∑∞k=−∞x(k)h(n−k) that gives the response y(n) of the LTI system as the function of the input signal x(n) and the unit sample response h(n) is known as ______________

a) Convolution sum

b) Convolution product

c) Convolution Difference

d) None of the mentioned

11. x(n)*(h_{1}(n)*h_{2}(n))=(x(n)*h_{1}(n))*h_{2}(n).

a) True

b) False

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