fft of a dat file?

Steven D'Aprano steven at REMOVE.THIS.cybersource.com.au
Wed Mar 25 07:45:03 CET 2009


On Wed, 25 Mar 2009 11:26:00 +0530, Soumen banerjee wrote:

> Hello,
> I'm kind of new to python and i wanted to do a little project, make a
> frequency plot of some wav audio. I have been following this webpage
> http://www.acronymchile.com/sigproc.html and have got to the making of a
> dat file containing the samples and time of sampling. The question here
> is how do i use FFT.fft to actually take an fft of this dat file since
> the first two lines are useless and also we have a \r\n after every
> sample. Also i would like some explanation on what FFT.fft expects as
> input. Does it expect the sampling times also or only the sampling
> values?


Did you follow the instructions in the webpage? I quote:

"Analysing the Signal
This is really quite easy, assuming you have Numerical Python and the FFT 
modules installed. Continuing from our last code snippet, where "out" 
contains a list of the samples from our sound file, the following gives 
us an FFT: 

import Numeric
import FFT
out_array=Numeric.array(out)
out_fft=FFT.fft(out)

It is as easy as that!"


Have you done this? Did it work? If not, what error did you get? If it 
did work, then what's the problem?


-- 
Steven



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