Dear Ladies and Gentlemen,
I am having an issue with designing a lead-lag controller. The bode plot of the continous controller is looking as expected but the discrete version of it is completely different and exhibits some weird spikes in the lower frequency section.
Margin of continous controller.
Bode plot of continous (blue) and discrete controller (orange).
The Sampling period is 81 ns which i use in the c2d function (with ZOH).
Is this some kind of numerical error or am I missing and/or misunderstanding something really important here?