Erik de Castro Lopo wrote: >On Wed, 5 Nov 2003 10:54:58 +0100 (CET) >Tim Goetze <[EMAIL PROTECTED]> wrote: > >> i feel the need to clarify/correct myself: the filters employed are >> not chebyshev designs, they were designed the same way as 'unmatched': >> frequency response given, iteratively approximate the filter. >> >> they do a lot better than chebys of the same order, but it's quite >> impossible to recalculate their coefficients at runtime. if that is >> demanded, the polyphase design probably wins easily. > >Tim, do you have any more info about this filter design procedure? I've >currently got a nasty filter design problem that I'm looking for a >solution for.
second part of chapter 26, http://dspguide.com/ has the algorithm. takes some fiddling for every filter you use it for, but it usually is worth the effort. i have a python implementation of the algorithm if you like that better than BASIC (FFT and IIR work is done in a largish, somewhat unpolished and unreleased-yet c++ lib of mine). tim
