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Re: Extract Coefficients of Fourier Series

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  • Subject: [mg58865] Re: Extract Coefficients of Fourier Series
  • From: "Dana DeLouis" <delouis at>
  • Date: Thu, 21 Jul 2005 03:08:15 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

Just for discussion, the function TrigFit has a small bug.  It's been around
for awhile, and was not corrected in 5.2.

My default setting for "FourierParameters" is set to something other than
the default of {0,1}.  This causes wrong output.  With TrigFit, the call to
Fourier does not use "FourierParameters", and makes the assumption that it
is using the Default setting {0,1}.

I recommend editing that file and adding the option "FourierParameters."
Instead of diving by Sqrt[len], and using the default setting, I recommend
just using the Data Analysis setting as below.


Change this line..

fcslist = Fourier[fcslist/Sqrt[len]];

To this.

fcslist = Fourier[fcslist, FourierParameters -> {-1,1}];




Dana DeLouis
Win XP & Office 2003



<mchangun at> wrote in message news:dbie2e$brj$1 at

> Hi All,
> I have a set of points which have I fitted to a fourier series with
> the TrigFit function.  This gives me a fourier series.  What I want is
> to extract all the coefficients of the series, square them, then sum
> them.  How do I this (more specifically, the extraction step?
> Thanks in advanced.

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