[sdiy] VCO reset time

[Don Tillman]

   > Date: Fri, 04 Jun 2004 11:30:03 -0400
   > From: harrybissell <harrybissell at prodigy.net>
   > 
   > I did a simulation of the trapezoid core and it indeed looks very
   > promising...  but correct me if I'm wrong
   > 
   > The two integrating capacitors have to be the same value
   > (precisely).  When I simulated one a little
   > bigger/smaller... performance degraded severely.  How will you
   > get around this issue ???

Any difference in capacitor values shows up as a proportional
difference in the slopes of the waveforms, so hand-matching the
capacitors will give you a more symmetrical waveform.  I hand-matched
the capacitors in my unit.

If you're extra concerned about waveform symmetry, and you might, I
would also recommend trimming the gain of the OTA's to match.

  -- Don

-- 
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com