(Comp.sys.hp48)
Item: 246
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  Resp: 2 of 2 by catto@author.ecn.purdue.edu
Author: [Erin S Catto]
  Date: Sat Dec 07 1991

Nyquists Plots:

Rather than using the canned (so-so) Nyquist programs I have found a better
way to do Nyquists on the HP48sx.  I use the PARAMETRIC plotting feature:

1)  Enter the open loop transfer function in terms of `s`.
2)  Store `i*w` into `s`.
3)  Make sure `w` is not resolvable.
4)  EVAL the transfer function.
5)  STO transfer function in `EQ`.
6)  Enter plotter.
7)  Select PARAMETRIC.
8)  Enter { w low high } INDEP.
9)  Press AUTO.
10) Decrease RES (decimals allowed) to increase resolution.
11) Change x,y range to change view.
12) Enter { w new_low new_high } to draw more or less.


                           It saves me time & effort -

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