15. The Z-transform function of a stable system is given as 3 -.1 2 - - z H(z) - (1- 2z-1)(1+ z--1) The impuse response hInj is

A. r u[-n + 1] u[n]

B. r u[-n - 1]+ (q-; u[n]

C. ?2" u[-n - 1] + (T) u[n]

D. 2" u[n] - (if u[n]

16. A causal system has input x[n] = (-3)" u[n] and output[An] = [4(2)1) uini The impulse response of this system is

A. [7(-2I )n 1?(-211 u[n]n

B. [7(2") ? 10(2-) urn]2

C. [10 ?)2 ? 7(2)2] u[n]2

D. [10(2" ? 7(.1-)1 u[n] 2

17. The transfer function of a system is given z(3z ? 2) by H(z)=4 The system is

A. causal and stable

B. causal, stable and minimum phase

C. minimum phase

D. none of the above

18. The transfer function of a system is given 2(z+ ?1) 2 as H(z) ? 1Consider the two statements : Statement (A) : System is causal and stable Statement (B) : Inverse system is causal and stable The correct option is

A. is true

B. is true

C. Both are true

D. Both are false

19. Given the z-transforms z(8z ?7) X(z) ? 4z2 ?7z+3 The limit of x[001 is

A.1

B.2

C.0

D.0

20. A low-pass filter circuit is basically

A. a differentiating circuit with lot time constant

B. a differentiating circuit with larger time constant

C. an integrating circuit with low time constant

D. an integrating circuit with larger time constant

21. Consider the following statements regarding a discrete system with the output input relationship y(n) = x(n) + 3. The system 1. is linear 2. is causal 3. has bonded for bounded input 4. is non-realisable Of these statements

A. 1, 2 and 3 are correct

B. 2 and 3 are correct

C. 1 and 2 are correct

D. 1, 3 and 4 correct

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