# Electronics and Communication Engineering - Signals and Systems - Discussion

Discussion Forum : Signals and Systems - Section 1 (Q.No. 1)
1.
What about the stability of system in
system is stable
unstable
stable at 0.4
cant say
Explanation:

ROC include the unit circle hence it is stable.

Discussion:
49 comments Page 1 of 5.

Abdul Wahab said:   1 week ago
The System is unstable,

Since, the pole at z = 0.4 lies inside the unit circle and the other pole at z = 2 lies outside the unit circle.

For a system to be stable, all the poles must be inside the unit circle in the z-plane.

Therefore, the system is unstable.
(1)

Usama said:   3 years ago
H(z) is actually z transform. Now finding the ROC:
The roots are 0.2, 2.
which makes a circle that encloses the unit circle, so the system is stable.
(1)

Moni said:   3 years ago
Find ROC by using partial differentiating it gives two poles both are causal so the greatest pole is roc that means z>2, should lie outside the circle. It is unstable.

Salman said:   4 years ago
The ROC for the non causal signal is? Can anyone answer this?

Tushar said:   4 years ago
According to me, it is Unstable.

Mosin said:   4 years ago
What is Roc?

If we use control systems topic here.

The system is stable because all poles are lying on the right-hand side.

Moovendran said:   4 years ago
Pole is Z=2.

Meena chintha said:   5 years ago
Pole is Z=2, the unit circle is 1. So it is unstable.

Then how, it should be stable? Explain it.

Aiyoob said:   5 years ago
All poles are in the left half of s plane.

So, Use the concept of control system.

Ramasubramanian said:   5 years ago
The system is unstable since the pole z=2 lies outside the UNIT circle.