Some functions do not get mapped properly

[terdinatore]

Grüezi Thomas,

While testing your document, I stumbled upon a few functions that do not get mapped properly.

Specifically I wanted to plot an 2nd order all-pass (s^2-s+1)/(s^2+s+1) and a 2nd order notch (s^2+1)/(s^2+s+1)

I do not expect a fix but just wanted leave this as a note in case someone else runs into these issues, too.

[jdocampom]

You absolute legend! Thanks a lot for this