control.nyquist

control.nyquist(syslist, omega=None, Plot=True, color='b', labelFreq=0, *args, **kwargs)

Nyquist plot for a system

Plots a Nyquist plot for the system over a (optional) frequency range.

Parameters:

syslist : list of LTI

List of linear input/output systems (single system is OK)

omega : freq_range

Range of frequencies (list or bounds) in rad/sec

Plot : boolean

If True, plot magnitude

labelFreq : int

Label every nth frequency on the plot

*args, **kwargs:

Additional options to matplotlib (color, linestyle, etc)

Returns:

real : array

real part of the frequency response array

imag : array

imaginary part of the frequency response array

freq : array

frequencies

Examples

>>> sys = ss("1. -2; 3. -4", "5.; 7", "6. 8", "9.")
>>> real, imag, freq = nyquist_plot(sys)