On Thursday, July 12, 2012 8:37:34 PM UTC-7, zohasaba wrote:
> Hi everybody
> 
> I'm trying to compute plot 1/3 octave frequency of wave file . As anyone any idea about the right algorithm?
> Thanks a lot

If you Google on:

1/3 octave filter

you will find explanations of fractional octave filters, codes for such filters and homework assignments to familiarize yourself with such filters.

Dale B. Dalrymple

zohasaba wrote:

> I'm trying to compute plot 1/3 octave frequency of wave file . As anyone
> any idea about the right algorithm?

- read the wave file
- do a fourier transform and store the result in an spectrum array
- create an array of 1/3 octave values
- fill this array from the spectrum array data:
    - sum up all values in the spectrum array whose frequency belongs into 
      one specific octave value point. 
    - Put this sum into the octave value array. 
    - repeat this for all octave value points

bye
Andreas
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On Thu, 12 Jul 2012 22:37:34 -0500, zohasaba <zoha_saba@yahoo.com>
wrote:

>Hi everybody
>
>I'm trying to compute plot 1/3 octave frequency of wave file . As anyone any idea about the right algorithm?
>Thanks a lot
>

If you can read MATLAB code there are a few examples in the File
Exchange.

I found this one and I have seen others.

http://www.mathworks.com/matlabcentral/fileexchange/19228-short-time-fft-with-octave-smooth

Mark DeArman

Hi everybody

I'm trying to compute plot 1/3 octave frequency of wave file . As anyone any idea about the right algorithm?
Thanks a lot