Hello, I was curious if anyone else had run into this issue. It seems that if you try to do a nyquist diagram when there is an s-term by itself in the denominator (a pole at zero), Matlab mistakenly tries to use that value (instead of detouring around it), and produces an incorrect plot. For example, ....................1 G(s) = ----------------- ..........(s)(s + 3)(s + 5) Will produce the wrong nyquist plot. http://www.engin.umich.edu/group/ctm/freq/nyq.html" The same website provides a new function called http://www.engin.umich.edu/group/ctm/extras/nyquist1.html" which was supposed to fix the problem, but the code has an error (it's kind of outdated), and the code is a little over my head in terms of troubleshooting. I know it's a long shot, but I was hoping someone else had run into this and was able to provide a solution.