Web-Based Control System Analysis and Design
## Margin

#### DESCRIPTION:

The function calculates and plots the minimum gain margin, phase margin,
and corresponding crossover frequencies of an SISO system. The gain margin is the factor
by which the gain K can be raised before the system becomes unstable. It can be calculated
from 1/G(*jw*), where |G(*jw*>)| is the magnitude at frequency w which makes the
phase angle of G(*jw*) equal to -180 degrees.

Similarly, the phase margin is another measure which is used to indicate the stability
margin of a system. It can be calculated from the phase of G(*jw*)-180 degrees at
frequency w which makes the magnitude |G(*jw*)| equal to 1.0. The frequency w is
then called crossover frequency.

Please select a model to represent the system: