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Topic: Need help in doing fft for a large matrix
Replies: 2   Last Post: Feb 7, 2013 2:06 PM

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Derek Goring

Posts: 3,922
Registered: 12/7/04
Re: Need help in doing fft for a large matrix
Posted: Feb 7, 2013 2:06 PM
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On Friday, February 8, 2013 2:34:08 AM UTC+13, Gupta wrote:
> Hello...i ma trying to do abs(fft(y))) where y a large matriy of size 1x8388608. when i am running the code, at this line the program was getting terminated without running remaining commands. was the problem is with size of the matrix or memory of matlab or fft funtion. when i do this operation for a mtrix of size 1x4194304 it was working perfect.

Why are you even trying to take the FFT of such a long series?
The resulting spectrum will be so noisy, you won't be able to interpret it.
Split the signal into 10 or more blocks, take the FFT of each, then average the results and take the abs of the first half. This will give a nice smooth spectrum.

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