[Scilab-users] Is FPPO available ?

[Claus Futtrup]

Hi there

I have generated some 60 seconds of (pink) noise, sampled at 48 kHz, 
which I can fft to get a linear-frequency representation (predominantly 
interested in 20 - 20k Hz).

If I plot this data on a log-frequency plot, then of course high 
frequency spectrum plots look very noisy.

I need a fixed-point-per-octave (FPPO) transformation of my data so I 
can study the spectrum better at higher frequencies with a more readable 
trace of my frequency response data. I would be interested in for 
example a 1/3 octave moving-average smoothing.

In effect, the FPPO technique utilizes a measurement time window that 
varies as a function of frequency, utilizing a long time window at low 
frequencies (for narrow frequency resolution) and a successively shorter 
time window at high frequencies (but averaged through the entire 60 
seconds).

Is FPPO available in Scilab? (Signal Processing Toolbox maybe?) ... I 
cannot find it.

/Claus

P.S. You could see this PDF file for some pictures (go to page 6, Figure 4):
http://www.rationalacoustics.com/files/FFT_Fundamentals.pdf

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