(Comp.sys.hp48) Item: 246 ---------- 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 - Zoom