Multiplexed Sample and Hold Resonator? (was New Filter Designs)

[Paul Perry]

This thread reminds me of an idea I had for a vocoder,
after seeing a switched resistor filter in Lancaster's CMOS
Cookbook.
The filter was tuned by pulsewidth modulating resistors with
CMOS switches at ultrasonic rates.
It occurred to me, that if you moved the operating freq even higher,
so you could fit several operations in, and multiplex the 
cpacitors in the ckt, which are the only part with any memory.

Perhaps with today's higher freq op amps, and better switches,
this is viable. Of course, you could do the same for the 
envelope followers etc.

A four op amp vocoder? I'd like to see that!

paul perry Melbourne Australia