# Electronics and Communication Engineering - Signals and Systems

### Exercise :: Signals and Systems - Section 1

11.

The z-transform of a particular signal is given where The system after implementation will be

 A. casual and stable B. non-casual and stable C. non-casual and unstable D. casual and unstable

Explanation:     Include unity circle and exterior of circle hence x(z) will be stable, causal.

12.

The system with given pole-zero diagram is A. casual B. non-casual C. both sided D. not-possible

Explanation:

Because no.of zero is more than Pole, therefore when you find transfer function.

Numerator power will higher than denominator, and such transfer functions is not realizable.

13.

A pole zero pattern of a certain filter is shown in figure. This filter must be A. LPF B. BFP C. HPF D. APF

Explanation:

In transfer function, no of zeros = no. of poles, hence it is all pass fliter.

14.

If transfer function of a system is H(z) = 6 + z-1 + z-2 then system is

 A. minimun phase B. maximum phase C. mixed phase D. none

Explanation:

H(z) = 6 + z-1 - z-2, solve it by considering H(z) = 0 z = 1/3, -1/2 in H(z) only numerator.

Hence z = 1/3, - 1/2 will be zero, and if zero lies inside the unit circle, system will be of minimum phase.

15.

The period of the function cos is

 A. B. 8s C. 4s D.  .