Idea for a CV quantizer

Don Tillman don at till.com
Wed Feb 28 20:53:01 CET 1996


   From: Haible_Juergen
   Date: Wed, 28 Feb 96 18:45:00 PST

   >One word: drift.

   the integrator would be reset to zero every millisecond,
   so this one shouldn't drift away.

Oh okay, I misunderstood your idea. Yeah, it should be fine.

But you can simplifiy it a lot; since you'll be S/H-ing anyway you
don't really need a stepping integrator.  Use a regular sawtooth
integrator, a counter, a comparator, a S/H, and only allow the S/H to
be triggered on the counter clock pulse.  Easy.


The reason I misunderstood it was because I had a preconceived idea in
my mind of a closed loop system, where the DAC (or your pulse
integrator) output gets compared to the input voltage and you goose
the counter (or integrator) when the difference between the input
signal and the DAC/integrator output is beyond one quantum, high or
low.

I think this approach simplifies things, but the drift wouldn't allow
the pulse integrator approach to work, it would have to be a DAC.  It
can also have variable hysteresis, if that might be considered a
feature.

I'm also thinking there must be a way to use a standard successive-
aproximation DAC chip with no extra hardware.

  -- Don













More information about the Synth-diy mailing list