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Subject: Re: Ifft on modified array fails
Date: Sat, 7 Nov 2009 15:12:01 +0000 (UTC)
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"Travis Bland" <travisbland88@yahoo.com> wrote in message <hd2rdu$l9g$1@fred.mathworks.com>...

> high_bin = ceil(high_bin);
> low_bin = floor(low_bin);
> 
> 
> 
> for i = 1:high_bin;
>     freq100(i) = 0;
> end
> 
> 
> for p = (N - high_bin):(N - low_bin);
>     freq100(p) = 0;
> end 
> 

I don't see anything symmetric in this truncation. 

The important thing to remember is that, for a given index k, if you set 
freq100(k)=0, then you must also set 
freq100(N+1-k)=0 to preserve conjugate symmetry of the spectrum. 

So, if you set freq100(1:high_bin)=0, as above, you must also set
freq100(N+1-(1:high_bin))=0 as well