Re: [LAD] A short technote on digital state-variable filters

From: Gordonjcp <gordonjcp@email-addr-hidden>
Date: Sun Nov 22 2020 - 00:17:31 EET

On Thu, Nov 19, 2020 at 10:05:00PM +0100, Fons Adriaensen wrote:
> Hello all,
>
> Some people have asked me to provide a bit more documentation
> on the state-variable filters I used in zita-eq1 and zita-jacktools.
>
> So I've written a short technical note on this. You can find it at
>
> <http://kokkinizita.linuxaudio.org/papers/digsvfilt.pdf>

I wish I was good at maths! This makes it all look so simple, and it works well.

I guess with the corrected parameters, you can't get it to self-oscillate without Q really being infinite? With the uncorrected parameters it seems to go "over unity" with Q set to about 10, but a soft clipper would stop it blowing up.

It behaves well if you interpolate the c1 and c2 values to sweep the filter across a block of samples, which is handy.

-- 
Gordonjcp
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev@lists.linuxaudio.org
https://lists.linuxaudio.org/listinfo/linux-audio-dev
Received on Sun Nov 22 04:15:01 2020

This archive was generated by hypermail 2.1.8 : Sun Nov 22 2020 - 04:15:01 EET