question for theorists: zeros & phase

[Martin Czech]

O, now I'm sure that I have to avoid singularities alltogether.  I'll let
the computer  compute phase before and after but not while sitting just
in that point (if this will happen at all).
 
After all that was written this is the only remedy.


What remains is the problem of how to continue the graph:
I could have come to the new phase via -180 or 180 DEG turn.

I guess this is comming into the same direction,
poles and zeros on the imag axis/unit circle are not allowed
for a defined system (component/parameter tolerances).

m.c.