pink noise

Started by Karl September 28, 2004
Hi ALL

I need an algorithm to generate pink noise (a drop of 20dB/decade) from
white noise (use in simulink) that is suitable for a frequency range of 1 to
100 Hz. Any suggestion is appreciated.

Regards

Karl


Actually, pink noise has a 10dB/decade drop-off.
See: http://www.firstpr.com.au/dsp/pink-noise/

"Karl" <Karl@Karl.com> wrote in message
news:4159e495$0$11918$c3e8da3@news.astraweb.com...
> Hi ALL > > I need an algorithm to generate pink noise (a drop of 20dB/decade) from > white noise (use in simulink) that is suitable for a frequency range of 1 to > 100 Hz. Any suggestion is appreciated. > > Regards > > Karl
Karl wrote:

> Hi ALL > > I need an algorithm to generate pink noise (a drop of 20dB/decade) from > white noise (use in simulink) that is suitable for a frequency range of 1 to > 100 Hz. Any suggestion is appreciated. > > Regards > > Karl
20 dB/decade is easy to generate; an integrater does that. It's not what you want, however, but red noise. Pink noise is decreases at 10 dB/decade. There's a modestly amusing discussion of colored noise at http://ccms.ntu.edu.tw/~karchung/Phonetics%20II%20page%20sixteen.htm Jerry -- ... they proceeded on the sound principle that the magnitude of a lie always contains a certain factor of credibility, ... and that therefor ... they more easily fall victim to a big lie than to a little one ... A. H. &#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;&#2013266071;
Karl,

If I remember correctly, when using the algorithm on the page mentioned
below, design the filter to run at a slow rate to get better precision.  If
your rate is too high, your filter is pretty sloppy.  You can interpolate
the output of the filter to the rate needed and then add it to any AWGN that
may also be present.

I think that I found a flicker noise block on the web somewhere (in
simulink).  I'll post the URL if I find it.  I'll also post a link to the
paper that addresses algorithm if I find it.

Regards,
Phil

"Jon Harris" <goldentully@hotmail.com> wrote in message
news:2ru9jrF1ejreuU1@uni-berlin.de...
> Actually, pink noise has a 10dB/decade drop-off. > See: http://www.firstpr.com.au/dsp/pink-noise/ > > "Karl" <Karl@Karl.com> wrote in message > news:4159e495$0$11918$c3e8da3@news.astraweb.com... > > Hi ALL > > > > I need an algorithm to generate pink noise (a drop of 20dB/decade) from > > white noise (use in simulink) that is suitable for a frequency range of
1 to
> > 100 Hz. Any suggestion is appreciated. > > > > Regards > > > > Karl > >
"Phil" <phil_simulink@(NOSPAM)sympatico.ca> wrote in message
news:<Njm9d.33273$HO1.1431248@news20.bellglobal.com>...
> Karl, > > If I remember correctly, when using the algorithm on the page mentioned > below, design the filter to run at a slow rate to get better precision. If > your rate is too high, your filter is pretty sloppy. You can interpolate > the output of the filter to the rate needed and then add it to any AWGN that > may also be present. > > I think that I found a flicker noise block on the web somewhere (in > simulink). I'll post the URL if I find it. I'll also post a link to the > paper that addresses algorithm if I find it. > > Regards, > Phil > > "Jon Harris" <goldentully@hotmail.com> wrote in message > news:2ru9jrF1ejreuU1@uni-berlin.de... > > Actually, pink noise has a 10dB/decade drop-off. > > See: http://www.firstpr.com.au/dsp/pink-noise/ > > > > "Karl" <Karl@Karl.com> wrote in message > > news:4159e495$0$11918$c3e8da3@news.astraweb.com... > > > Hi ALL > > > > > > I need an algorithm to generate pink noise (a drop of 20dB/decade) from > > > white noise (use in simulink) that is suitable for a frequency range of > 1 to > > > 100 Hz. Any suggestion is appreciated. > > > > > > Regards > > > > > > Karl > > > >
There is a contributed library on the Mathworks site that contains a flicker noise model. http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=261&objectType=file The flicker noise is in the Nonidealities library in rf.mdl. The block description contains a reference to the paper from which the basic algorithm is derived. Regards, Phil