Take the 2-minute tour ×
Mathematica Stack Exchange is a question and answer site for users of Mathematica. It's 100% free, no registration required.

Could anyone tell me how to use NyquistPlot with a first argument that is not a transfer function model? The expression I'd like to pass to NyquistPlot is Exp[z]Cos[z].

share|improve this question
    
What does the expression represent? A sinusoidal transfer function, discrete-time transfer function, something else? eg, try Off[TransferFunctionModel::npnd] NyquistPlot[Exp[z] Cos[z], SamplingPeriod -> 1] if it's a discrete-time system with sampling period 1. –  Suba Thomas Nov 22 '13 at 15:23

1 Answer 1

Nyquist plots usually require rational functions (i.e., ratios of polynimials). I suppose if you know what you are doing, you could approximate this with a Taylor series expansion:

NyquistPlot[Normal[Series[Exp[z] Cos[z], {z, 0, 6}]]]  

enter image description here

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.