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

[Andrew Simper]

On 6 March 2014 02:40,  <blacet at blacet.com> wrote:
> As far as I know, the state variable filter design is the only one that
> has simultaneous outputs as you require. This is a 12dB design with two
> stages, although with enough feedback/Q, the apparent slope is much
> greater.

You can make 4 pole SVFs that contain 4 integrator stages and produce
H4 L4 H1L3 H2L2 H3L1, and you can then sum and difference H4 and L4 to
create allpass and notch.