Forums

IIR filter design libray

Started by CoCo January 19, 2005
Hi,

I'm currently looking for a PC software library that can be used to
dynamically design IIR filters such as Butterworth, Chebychev,
Elliptic ...

I can't find something that is very well kown. I'm astonished that
there is no (or very few) popular libraries to face such a common
problem. Does somebody know such a library ?

The libray I'm looking for should :
- provide routines able to provide IIR filters coefficients from high
level specifications (filter type, order, transition bands, bandpass
and bandstop ripple ...)
- be well known and/or supported by a reliable company/group
- be used, tested and validated by numerous users
- have an interface for Delphi, but I can also deal with C or C++
- be shipped with a extensive set of test routines
- be as cheap as possible, but this is not the main point

Thank you for your inputs


Olivier Cochelin
Notocord Systems
Hi!

www.dewresearch.com

If you can find something better let me know <g>

Regards!
Atmapuri

"CoCo" <coco_corp@yahoo.fr> wrote in message
news:af247ee9.0501190017.28cf75ea@posting.google.com...
> Hi, > > I'm currently looking for a PC software library that can be used to > dynamically design IIR filters such as Butterworth, Chebychev, > Elliptic ... > > I can't find something that is very well kown. I'm astonished that > there is no (or very few) popular libraries to face such a common > problem. Does somebody know such a library ? > > The libray I'm looking for should : > - provide routines able to provide IIR filters coefficients from high > level specifications (filter type, order, transition bands, bandpass > and bandstop ripple ...) > - be well known and/or supported by a reliable company/group > - be used, tested and validated by numerous users > - have an interface for Delphi, but I can also deal with C or C++ > - be shipped with a extensive set of test routines > - be as cheap as possible, but this is not the main point > > Thank you for your inputs > > > Olivier Cochelin > Notocord Systems
coco_corp@yahoo.fr (CoCo) wrote in 
news:af247ee9.0501190017.28cf75ea@posting.google.com:

> Hi, > > I'm currently looking for a PC software library that can be used to > dynamically design IIR filters such as Butterworth, Chebychev, > Elliptic ... > > I can't find something that is very well kown. I'm astonished that > there is no (or very few) popular libraries to face such a common > problem. Does somebody know such a library ? > > The libray I'm looking for should : > - provide routines able to provide IIR filters coefficients from high > level specifications (filter type, order, transition bands, bandpass > and bandstop ripple ...) > - be well known and/or supported by a reliable company/group > - be used, tested and validated by numerous users > - have an interface for Delphi, but I can also deal with C or C++ > - be shipped with a extensive set of test routines > - be as cheap as possible, but this is not the main point > > Thank you for your inputs > > > Olivier Cochelin > Notocord Systems
I have used a program from Momentum Data Systems for many years called QEDesign. It is very good at creating filter coefficient files. It might work for your application. www.mds.com -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
CoCo wrote:
> > Hi, > > I'm currently looking for a PC software library that can be used to > dynamically design IIR filters such as Butterworth, Chebychev, > Elliptic ...
ON Linux you could try http://www.watri.org.au/~ajh/libfilth/ It may not be pssible to get it to compile on windows. Erik -- +-----------------------------------------------------------+ Erik de Castro Lopo nospam@mega-nerd.com (Yes it's valid) +-----------------------------------------------------------+ "Cunnilinugus and psychiatry brought us to this." -- Tony Soprano in HBO's "the Sopranos"
ONEoverT is a good package. I seem to recall that Tyder were selling a
DSP library at one time.

Bob
CoCo wrote:
> Hi, > > I'm currently looking for a PC software library that can be used to > dynamically design IIR filters such as Butterworth, Chebychev, > Elliptic ... > > I can't find something that is very well kown. I'm astonished that > there is no (or very few) popular libraries to face such a common > problem. Does somebody know such a library ? > > The libray I'm looking for should : > - provide routines able to provide IIR filters coefficients from high > level specifications (filter type, order, transition bands, bandpass > and bandstop ripple ...) > - be well known and/or supported by a reliable company/group > - be used, tested and validated by numerous users > - have an interface for Delphi, but I can also deal with C or C++ > - be shipped with a extensive set of test routines > - be as cheap as possible, but this is not the main point > > Thank you for your inputs > > > Olivier Cochelin > Notocord Systems
Thanks for the link Erik. The manual is a good overview of a lot of filter
design techniques.
Cheers, Syms.
p.s. Going down your post, it's spelt 'Cunnilingus'! ;-)
"Erik de Castro Lopo" <nospam@mega-nerd.com> wrote in message
news:41EEC16E.8C127D52@mega-nerd.com...
> > ON Linux you could try > > http://www.watri.org.au/~ajh/libfilth/ > > It may not be pssible to get it to compile on windows. > > Erik > -- > +-----------------------------------------------------------+ > Erik de Castro Lopo nospam@mega-nerd.com (Yes it's valid) > +-----------------------------------------------------------+ > "Cunnilinugus and psychiatry brought us to this." > -- Tony Soprano in HBO's "the Sopranos"
Many thanks to all of you. Your proposals were useful.

Just to make things clearer, what I'm looking for is a software
library that can be called from code of my own. Indeed, in my
application, filters need to be design dynamically to meet user
requirements.
Stand alone software that can be used to design filters (such as
Matlab does for example) is not a suitable solution for me.

Wide usage and good support of the library is a key point.


Olivier Cochelin
Notocord Systems
Making adjustable IIR filters is tricky.  Depending on adjustments, the 
filters may transition through an unstable region with unpredictable results.  
This problem doesn't exist with FIR filters.  I have done something similar 
using a FIR filter and the Parks-McClellan algorithm.  Worked for a three kHz 
bandwith in real time.  

In article <af247ee9.0502101004.2010fa60@posting.google.com>, 
coco_corp@yahoo.fr (CoCo) wrote:
>Many thanks to all of you. Your proposals were useful. > >Just to make things clearer, what I'm looking for is a software >library that can be called from code of my own. Indeed, in my >application, filters need to be design dynamically to meet user >requirements. >Stand alone software that can be used to design filters (such as >Matlab does for example) is not a suitable solution for me. > >Wide usage and good support of the library is a key point. > > >Olivier Cochelin >Notocord Systems
in article D0SUd.15651$VD5.13664@twister.socal.rr.com, George Bush at
george.w.bush@whitehouse.com wrote on 02/28/2005 23:16:

> Making adjustable IIR filters is tricky. Depending on adjustments, the > filters may transition through an unstable region with unpredictable results.
not for Direct Form 1 or Direct Form 2 or Lattice or Normalized Ladder, or the Gold-Rader architectures. unless there is overshoot in the coefficient slewing (which won't happen for linear slewing nor for 1st order LPF slewing), even as the denominator coefficients are slewed from one stable value to another, *none* of the values in between are unstable. this has been discussed before, but it was so long ago that i wouldn't know where to begin Googling. now E-mu's Dave Rossum (or maybe it was Jean Larouche) did a paper that there is temporary instability in some cases due to the movement of the coefficients. but any static value in between stable endpoints is stable. -- r b-j rbj@audioimagination.com "Imagination is more important than knowledge."
CoCo wrote:
> Many thanks to all of you. Your proposals were useful. > > Just to make things clearer, what I'm looking for is a software > library that can be called from code of my own. Indeed, in my > application, filters need to be design dynamically to meet user > requirements. > Stand alone software that can be used to design filters (such as > Matlab does for example) is not a suitable solution for me.
Along the same lines -- does anyone know where to find algorithms for numerically transforming LP IIR prototypes into highpass, bandpass and bandstop filters? I don't want packages that do the job for me, I want to be able write my own package. Rune