[sdiy] Auto Center waveforms

[Tim Parkhurst]

On Tue, Jul 14, 2009 at 6:45 AM, Jerry Gray-Eskue<jerryge at cableone.net> wrote:
>
> I have been thinking about centering arbitrary wave shapes on 0 volts.
>
> Wave shapers and some VCO waveforms tend to create waveforms with a dc
> offset and it would be nice to have a circuit that would "balance" these so
> that the sum of the + voltage = the sum of the - voltage.
>

Hey Jerry,

If you're dealing with a VCO, does the offset get better or worse over
a certain CV range? What I'm thinking is that you could plot the
offset vs. frequency and maybe come up with a relatively simple offset
compensation by taking some fraction of the control voltage. A simple
voltage divider feeding a portion of the CV to a summing amp on the
output might do the trick. Hopefully the offset you're seeing is
relatively linear and you won't have to resort to any multiplying or
squaring tricks to come up with an offset compensation curve. Worth a
shot?


Tim (relatively linear, except on Tuesdays) Servo
-- 
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- H.L. Hastings