show_margins display gain and phase margin and associated crossover frequencies

## Syntax

                show_margins(h)
                show_margins(h,'bode')
                show_margins(h,'nyquist')

## Arguments

h

  a SISO linear system (see :syslin).

## Description

Given a SISO linear system in continuous or discrete time, `show_margins` display gain and phase margin and associated crossover frequencies on a bode (the defaut) or nyquist representation of the frequency response of the system.

## Examples

    //continuous case
    h=syslin('c',0.02909+0.11827*%s+0.12823*%s^2+0.35659*%s^3+0.256*%s^4+0.1*%s^5,..
                 0.0409+0.1827*%s+1.28225*%s^2+3.1909*%s^3+2.56*%s^4+%s^5);
    show_margins(h)
    show_margins(h,'nyquist')

h=syslin('c',0.02909+0.11827*%s+0.12823*%s^2+0.35659*%s^3+0.256*%s^4+0.1*%s^5,.. 0.0409+0.1827*%s+1.28225*%s^2+3.1909*%s^3+2.56*%s^4+%s^5); show_margins(h) show_margins(h,'nyquist')

    //discrete case
    h = syslin(0.1,0.01547+0.01599*%z ,%z^2-1.81*%z+0.9048)
    show_margins(h)
    show_margins(h,'nyquist')

h = syslin(0.1,0.01547+0.01599*%z ,%z^2-1.81*%z+0.9048) show_margins(h) show_margins(h,'nyquist')

## See also

- p_margin
- g_margin
- bode
- nyquist