[sdiy] Good 24db/oct HP-LP-BP-Notch filter Schematics ??

[Neil Johnson]

Richie wrote:

> More likely option 2 if the product has a single global feedback path in
> which you can insert an external processor.  The 4-pole SVF is a "leapfrog"
> arrangement with multiple feedback paths if I remember correctly.

It's horrendous - the maths is taking some time to crunch
successfully...not helped by not having much spare time at the
moment...

Rane have an app note with the design of a 4-pole SVF, and some guy in
Finland designed one for his masters thesis.  But in both cases the
frequency and damping are fixed.  Turning them into successfully
controllable Freq and Q SVFs is a bit more of a challenge :)

Neil
--
http://www.njohnson.co.uk