Oh thanks, it is great !!!
----- Original Message ----- From: "Jer Welter" mrjester@fledge.watson.org To: "Thomas Goepfer" totoetlititi@free.fr Cc: pd-list@iem.at Sent: Thursday, March 18, 2004 11:11 PM Subject: Re: Fw: [PD] about filtergraph~
Anyone does know how calculate the parameters of a biquad filter from
the
center frequencie, bandwith and quality ?
Here are two references that may help: http://aulos.calarts.edu/pipermail/music-dsp/1997-July/019624.html http://www-ccrma.stanford.edu/~jos/filters/BiQuad_Section.html
The first is Robert Bristow-Johnson's BiQuad "cookbook recipes" for the various kinds of filter (such as lowpass, bandpass, highpass, shelving - is this what you mena by "quality"?)
The second is the section of Julius Smith's Digital Filtering text on biquads. The text as a whole is a very informative read.
Jer