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From: Greg Heath <heath@alumni.brown.edu>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Matlab FFT Calibration Routines
Date: Mon, 5 May 2008 14:12:58 -0700 (PDT)
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On May 5, 4:29=A0pm, "John Costello" <JohnCoste...@ChampAero.com> wrote:
> Does Matlab have a canned set of data for FFT analysis?
>
> What I am trying to find is a Matlab program that takes a
> known set of data for a signal, computes the FFT and
> extracts the spectral content and RMS equivalents of the
> discrete sinusoids used to assimilate the signal...
>
> For example, if we set up a known signal comprised of
>
> f(t) =3D 5 + 2sin(2*pi*100*t) + 3sin(2*pi*1000*t)
>
> what do we get from the Matlab FFT analysis?

What are you looking for?

Results depend on N and dt. The FFT imposed
period is

T =3D N*dt

Therefore, you should get the best results when
100*N*dt =3D integer.

t =3D dt*(0:N-1)';
df =3D 1/T
f =3D df*(0:N-1)';

Hope this helps.

Greg