question for theorists: zeros & phase

[Magnus Danielson]

From: Martin Czech <martin.czech at intermetall.de>
Subject: Re: question for theorists: zeros & phase
Date: Mon, 27 Sep 1999 13:56:47 +0200 (MET DST)

> 
> 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.

You should end up very close to the result of just passing by very close
(but not at) the pole/zero. But, then this depends on what side of the
pole/zero you pass it... I can't come up with a good pick here, they are
a cycle away... maybe just take a pick and stick with it?

> 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).

Allowed and allowed, they will not be there in the real system, just very
close. Actually what we used is some common sence on how a real implementation
actually behaves.

Cheers,
Magnus