On Feb 7, 2011, at 6:12 AM, volker böhm wrote:
On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote:I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc..hci've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~.vb <queryBiquad.js>
Thanks, that helped. Here's what I have so far: I got the mouse interaction almost completed, now I'm just starting the plotting part, which has a ways to go.
.hc
filterview.tcl
Description: Binary data
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