On Feb 7, 2011, at 12:43 PM, Hans-Christoph Steiner wrote:
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.
.hc
i'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>
I also just pushed my git to a public repo:
https://github.com/pd-projects/filterview
.hc
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