Re: [Scilab-users] Is FPPO available ?

2014-06-05 Thread Claus Futtrup

Hi Stefan et al.

What about wavelets?

Maybe wavelet toolbox? I am not so familiar with it - which wavelet 
function can do the per octave smoothing I ask for?


/Claus

On 04-Jun-14 21:17, Stefan Du Rietz wrote:

On 2014-06-04 21:09, Claus Futtrup wrote:


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


What about wavelets?

Stefan


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Re: [Scilab-users] Is FPPO available ?

2014-06-04 Thread Stefan Du Rietz

On 2014-06-04 21:09, Claus Futtrup wrote:


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


What about wavelets?

Stefan


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