(Comp.sys.handhelds)
Item: 2162 by wong at enel.ucalgary.ca
Author: [Raymond Wong]
  Subj: Re: Nyquist Plot Program
  Date: Fri Feb 22 1991

I have created two small programs for doing Nyquist plots, NYQL (does a line
plot) and NYQUIST (does a point plot).  Also in the directory is G, which is
the open-loop transfer function in terms of 'S'.  To do different equations
and values of gain just edit 'G'.  To plot in different ranges of frequency
(W) and step rates, simply change the values in the FOR STEP loop. Change plot
x/y parameters to approprate Real/Imaginary range of plot.

Hope this will help... although I'm sure it could be improved, at least it
gets the job done.