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From: "Vincenzo Manzoni" <ervincio@tiscali.it>
Newsgroups: comp.soft-sys.matlab
Subject: Re: PSD and sptool
Date: Mon, 6 Aug 2007 10:30:26 +0000 (UTC)
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>> at 10 Hz with power 0.5... that is theoretically corret.
 
> Show how you obtained that value.

I know the area below the power density spectrum is the
signal variance. Then:

Fs = 1024;
t = 0:1/Fs:1;
x = sin(2*pi*t*10);

var(x) -> 0.5

If I calculate the PSD with normalization of the article
which I have cited, 

sum(mx(:)) -> 0.5

My assumption is correct?

> However,
> unless we know exactly what you did and exactly what
sptool does,
> we can't do anything but guess.

In sptool, I import the same signal and I create the
spectrum with fft as choose (with the same number of sample
I use in when calculate the PSD without sptool).