Discrete Time Signals and Systems MCQs

Question 1

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

Accepted Answer

1

Answer

2

Answer

0

Answer

0

Question 2

A low-pass filter circuit is basically

Accepted Answer

an integrating circuit with low time constant

Answer

a differentiating circuit with lot time constant

Answer

a differentiating circuit with larger time constant

Answer

an integrating circuit with larger time constant

Question 3

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

Accepted Answer

1 and 2 are correct

Answer

1, 2 and 3 are correct

Answer

2 and 3 are correct

Answer

1, 3 and 4 correct

Question 4

The auto eorelation function of white noise is

Accepted Answer

a delta function

Answer

a constant

Answer

Gaussian

Answer

exp (? I t ) with usual notation

Question 5

The spectral density of white noise is

Accepted Answer

uniform

Answer

exponential

Answer

Poisson

Answer

Gaussian

Question 6

The Fourier transform of a Gaussian time pulse is 1 z2 ? z

Accepted Answer

Gaussian

Answer

Uniform

Answer

a pair of impulses

Answer

Rayleigh

Question 7

The z-transform of a system is H(z)= z- 0.2 If the ROC is VI < 0.2, then impulse response of the system is

Accepted Answer

?(O.2)n u(-n -I)

Answer

(0.2) u[n]

Answer

(0.2) u[-n -1]

Answer

-(0.2)" u(n)

Question 8

A causal LTI system is described by the difference equation 2yin] = ay[n -21- 2x[nl + 13x In -II The system is stable only if

Accepted Answer

u = 2, any value of 13

Answer

a= 2 PI < 2

Answer

lal = 2 IRI > 2

Answer

al = 2, any value of a

Question 9

The region of convergence of the z-transform of a unit step function is

Accepted Answer

IZI > 1

Answer

Z <1

Answer

(Real part of z) > 0

Answer

(Real part of z) < 0