I was wondering if it's possible to know the difference between order of numerator and order of denumerator of open loop transfer function W(s) using Nyquist criterion ('stable' poles/zeros are bothering me; basically is there a way to find out a number of poles and zeros of W(s))? I hope I've explained my problem good enough...Any help is appreciated.:)
Perhaps if you plot the Nyquist chart for some examples you concoct you might be able to answer this. Start off with a few poles, then introduce a zero midway between the poles and see what changes on the Nyquist plot, and so on. (Bear in mind that each pole contributes at most 90 degrees of lag.) If you search online I bet you'll find a free Nyquist plotter. I'm not pretending to know the answer; but that's how I would go about investigating it. Good luck!
Here's a basic free plotter. Having played around with it, I don't think Nyquist alone is going to help with what you asked. http://www.facstaff.bucknell.edu/ma...blems/Freq/Interactive/Freq6NyquistP01Int.htm