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From: "Chen Sagiv" <chensagivron@gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Strange Behavior in Phase Calculation
Date: Wed, 14 May 2008 06:49:02 +0000 (UTC)
Organization: Image Processing &#38; Math More
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Dear friends,

I have a strange phenomenon.
I have a cosine wave. I take two instances of it.

I call the first Case 1, where I have 10 cycles of this 
wave. Case 2 is 10 cycle + one extra point. 

Now, when I calculate the FT of both signals, I get a non 
zero imaginary value for the second case.

If I try to calculate the phase, and use either atan, 
atan2, angle and phase commands I get a linear phase. 

Isn't it Gibberish ? How does Matlab generate linear phase 
when the imaginary part of the FT is practically zero ? 

I would be happy to get comments on this issue.

Thanks,

Chen