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From:  Greg Heath <heath@alumni.brown.edu>
Newsgroups: comp.soft-sys.matlab
Subject: Re: PSD and sptool
Date: Sun, 05 Aug 2007 15:37:36 -0700
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On Aug 5, 7:35 am, "Vincenzo Manzoni" <ervin...@tiscali.it> wrote:
> >greg-heathpower-spectrum-scaling
>
> In this link
> (http://www.mathworks.com/support/tech-notes/1700/1702.html)
> the magnitude of fft is scaled by NFFT, while you, in your
> post, scale the fft by sqrt(NFFT).
>
> What is the difference? Thanks you for your help...

The difference is my convention yields the relations

Pxav  =  sum(PSD)/N   =  sumsqr(x)/N


Hope this helps.

Greg