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group delay equalizer

Started by bharat pathak January 13, 2008
Hi,

  Matlab has a function called iirgrpdelay which helps
  in designing iir group delay equalizer filters.

  Any idea as to how this function can be re-written
  for people who are not using matlab?

Bharat Pathak
"bharat pathak" <bharat@arithos.com> wrote in message
news:fs-dnX5z64XJUBTanZ2dnUVZ_hCdnZ2d@giganews.com...
> Hi, > > Matlab has a function called iirgrpdelay which helps > in designing iir group delay equalizer filters.
This is a shamanistic optimization which tries to match the group delay profile by the brute force tweaking of an allpass function.
> Any idea as to how this function can be re-written > for people who are not using matlab?
I am glad to see that there are still some real people who dare to live without MatLab. Vladimir Vassilevsky DSP and Mixed Signal Consultant www.abvolt.com
On Jan 13, 3:35 am, "bharat pathak" <bha...@arithos.com> wrote:
> > Matlab has a function called iirgrpdelay which helps > in designing iir group delay equalizer filters. > > Any idea as to how this function can be re-written > for people who are not using matlab? >
i can only suggest to start with the MATLAB source code (i might have an old copy) for iirgrpdelay() and all functions that it depends on, and translate to C or whatever language you like. remember the stupid MATLAB indexing origin property. you might be adjusting some indices by 1. you know, probably everyone here has some C++ programming enviroment: VC++, Objective-C, GNU. they already have C++ classes for math using complex variables and matrices. probably, there exists some nice utilities to plot functions of one or two variables and to input and output audio to/from hardware or files. someone should add the simple functionality of most of the SP Toolbox to these classes in C++. lot'sa work. i can't do it. r b-j
"bharat pathak" <bharat@arithos.com> writes:

> Hi, > > Matlab has a function called iirgrpdelay which helps > in designing iir group delay equalizer filters. > > Any idea as to how this function can be re-written > for people who are not using matlab? > > Bharat Pathak
You check to see if it's available in gnu octave. -- % Randy Yates % "Remember the good old 1980's, when %% Fuquay-Varina, NC % things were so uncomplicated?" %%% 919-577-9882 % 'Ticket To The Moon' %%%% <yates@ieee.org> % *Time*, Electric Light Orchestra http://www.digitalsignallabs.com
> >You check to see if it's available in gnu octave.
Randy, I have checked in gnu octave and this is one of the prime reasons for looking out. I have my own library of dsp functions in octave, which help me to do good amount of dsp design work. So I am always on lookout on which functions are missing, and this function happens to be one of them. Bharat Pathak www.arithos.com ~dsp Simplified.
On 13 Jan., 09:35, "bharat pathak" <bha...@arithos.com> wrote:
> Hi, > > &#2013266080; Matlab has a function called iirgrpdelay which helps > &#2013266080; in designing iir group delay equalizer filters. > > &#2013266080; Any idea as to how this function can be re-written > &#2013266080; for people who are not using matlab?
Hi Bharat You can use the FDLS method: http://apollo.ee.columbia.edu/spm/external/tipsandtricks/files/TandT_Jan2007.zip Regards, Andor
>Hi Bharat > >You can use the FDLS method: > >http://apollo.ee.columbia.edu/spm/external/tipsandtricks/files/TandT_Jan2007= >.zip > >Regards, >Andor
Andor, Sorry I do not have access to SPM. Regards Bharat Pathak
On 15 Jan., 14:37, "bharat pathak" <bha...@arithos.com> wrote:
> >Hi Bharat > > >You can use the FDLS method: > > >http://apollo.ee.columbia.edu/spm/external/tipsandtricks/files/TandT_... > >.zip > > >Regards, > >Andor > > Andor, > > &#2013266080; &#2013266080;Sorry I do not have access to SPM.
The link should be available to everybody (did you try?). I'm sure Greg can send you a copy of the article (else drop me an e-mail).
On Jan 15, 3:56&#2013266080;am, Andor <andor.bari...@gmail.com> wrote:

> You can use the FDLS method:
I have an old C-language implementation of FDLS that I could polish-up and make available, if there is enough interest. I've never tried FDLS for phase manipulation, but it should work. Greg Berchin
Greg Berchin <gberchin@sentientscience.com> wrote in news:91018b6d-0980-
4a7e-aab3-b6816ad7f21c@m34g2000hsb.googlegroups.com:

> On Jan 15, 3:56&#2013266080;am, Andor <andor.bari...@gmail.com> wrote: > >> You can use the FDLS method: > > I have an old C-language implementation of FDLS that I could polish-up > and make available, if there is enough interest. > > I've never tried FDLS for phase manipulation, but it should work. > > Greg Berchin >
Greg, you're a bit modest. Your FDLS method is very cool. It's described in detail in Streamlining Digital Signal Processing (Rick Lyons new tricks book). I'm sure people would like a polished up C version. I would be glad to include it (or a link) on Danville's signal processing resource page. Al Clark Danville Signal