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From: "Nasser M. Abbasi" <nma@12000.org>
Newsgroups: comp.soft-sys.matlab
References: <hcj73a$b5$1@fred.mathworks.com> <AwaHm.1482$%U3.1017@newsfe21.iad> <a220a52b-a008-4b16-acc7-0656a03275b3@w37g2000prg.googlegroups.com>
Subject: Re: About FFT and Even Function
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Date: Sun, 1 Nov 2009 10:52:20 -0600
Xref: news.mathworks.com comp.soft-sys.matlab:581623



"dbd" <dbd@ieee.org> wrote in message 
news:a220a52b-a008-4b16-acc7-0656a03275b3@w37g2000prg.googlegroups.com...
> 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

Ofcourse, I said above n=1:N-1 which is clearly wrong (the number of points 
is N now N-1 points), I meant to write n=0:N-1 to make it N points. I made a 
typo starting it from 1 not 0.

May be now you can try my formula? ;)  but watch for the index.

--Nasser