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From: dbd <dbd@ieee.org>
Newsgroups: comp.soft-sys.matlab
Subject: Re: About FFT and Even Function
Date: Sun, 1 Nov 2009 07:37:33 -0800 (PST)
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On Oct 31, 11:11 pm, "Nasser M. Abbasi" <n...@12000.org> wrote:
> ...
> If the data sequence itself is real and even (i.e. x[n]=x[N-n]) where N is
> ...
> --Nasser

Let's try that:

>> % Nassar's formula, N = 6, x[n] = x[N-n] for n=1:N-1
>> fft([1 2 3 2 1 0])'
ans =
   9.0000
  -2.0000 + 3.4641i
        0
   1.0000
        0
  -2.0000 - 3.4641i
>> % "FFT-even" version,  N = 6, x[n] = x[N-n+1] for n=2:N
>> fft([0 1 2 3 2 1])'
ans =
     9
    -4
     0
    -1
     0
    -4
>>

Dale B. Dalrymple