[sdiy] SVF & phase

[Ingo Debus]

patchell wrote:
 >     One thing for sure, you will have a difficult time making a 
filter with
 > zero change in phase.  You can make one that has a constant (or near
 > constant) time delay vs frequency, but that is about it (time delay and
 > phase shift are related)..  Your only hope may be in the digital 
domain,
 > using finite impulse response filters (a subject I am not at all 
familiar
 > with), but even with that, I am doubtful.

It is possible to build an analog FIR filter. Use S&Hs instead of the
data latches in the digital version, and attenuators/amplifiers for
the coefficient multipliers. It's still time-discrete, but analog.

A special case of this is a BBD ;-)


 > mark s wrote:
 >
 >
 >>greets,
 >>what are some options for building a state-variable filter with a
 >>better-than normal phase response ?

I'm wondering, what is "better" or "worse" regarding the phase
response of a synthesizer filter?

Ingo