From help-request at octave dot org Mon Oct 31 16:40:34 2005
Subject: unwrap problems
From: Ron Crummett <rcrummett at uidaho dot edu>
To: help at octave dot org
Date: Mon, 31 Oct 2005 14:38:30 -0800

Sorry about this repeated post, I posted on this a while ago and forgot 
to do anything about it.

I am having a problem using unwrap.  I am trying to plot the bode 
diagram and get phase wraparound:

H = tf([330 49.5], [1 20.015 100.3 1.5 0]);
w = logspace(-3, 3, 601);
[mag, ph] = bode(H, w);
semilogx(w, ph)

The plotting command plots a wrapped phase, it jumps from -180 to 180.  
I have tried using the unwrap command but it doesn't seem to do much; 
however, on further review it looks like it unwraps the phase in terms 
of radians, whereas the bode function returns the phase in degrees.

-Wouldn't it be easier if the bode function automatically called the 
unwrap function?  I have edited my bode.m script to do this and now 
everything works fine; is there a reason it hasn't been done?

-Ron



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