Hi Florian,

thanks for the links. Very intersting!

I'm planing a harmonizer to adding higher hamonics to a signal with a very special design. (don't know wheather it will sound good). High and low pass filters would be for pre and post filtering the drive signal and the pure added harmonics, where no resonance is needed.

I know those frequency controlled filters. Linear Technology offers some with linear phase behavior and already integrated oscillators, where the frequency can be set with an external resistor. But most don't operate in the audio frequency range ( http://www.linear.com/pc/viewCategory.jsp navId=H0,C1,C1154,C1008 )
But I haven't checked everyone, because I have very few time working on this project due to my studies at the moment.

Kind regards,
Olli

--- In Doepfer_a100@yahoogroups.com , Florian Anwander <fanwander@...> wrote:
>
> Hi olli
>
> via http://matrixsynth.blogspot.com/2010/12/diy-digital-synth-demo.html
> I stumbled over http://www.national.com/mpf/MF/MF10.html#Overview
>
> Needs a clock instead of CV, but a simple VCO (no extreme linearity is
> required for this kind of VCF) shouldn't be too difficult.
>
> I think it would be also extremely useful as anti aliasing filter for
> the BBD modules.
>
> Florian
>