Question

What does a gain margin close to unity or phase margin close to zero indicate?

Answer 1

A gain margin close to unity or phase margin close to zero indicate constant

Answer 2

A gain margin close to unity or phase margin close to zero indicates the system is highly oscillatory.

In the oscillating system, the force acts in an opposite direction to the displacement of the particle from the equilibrium point.

This force tends to change with time or it can be constant.