OK, My bad, dropped a digit. 0.0833 x 128 = 10.6624 volts
For Microtonal work you can always rescale the DAC reference to a smaller output range.
I guess we could put in a couple jumpers to change output and input range to 0 to 5 volts.
That should help interface to 5 volt systems.
Math
0.0833 x 64 = 5.3312 = 64 steps per semitone.
For 1 cent resolution, 0.0833 / 100 = 0.000833 ∗ 4096 = 3.4119 volts Vref
--- In ComputerVoltageSources@yahoogroups.com, "John Loffink" <jloffink@...> wrote:
>
> For a 12 bit output, that's 4096 steps in 10.625 volts full scale, or 2.59
> mV per step. A semitone is 1V / 12 = 83.33 mV. So that should be 32.17
> steps per semitone. In cents the resolution is 3.1 cents.
>
> I think there could be value in having a fixed programmable offset of half
> the full scale voltage, for LFO waveforms centered around zero. This could
> be tapped from the voltage reference (DACC does not have one onboard),
> toggled through an analog switch to an output op amp. To avoid effecting
> the accuracy of 0 to 10.625 volt scale output, one could feed that output
> directly to the switch, and feed the op amp/offset circuit to the other
> input to the switch. Or else simply run the two in parallel without any
> software control at all, doubling the number of output jacks, one each for
> 0-10 and +/-5 volts.
>
> John Loffink
> The Microtonal Synthesis Web Site
> http://www.microtonal-synthesis.com
> The Wavemakers Synthesizer Web Site
> http://www.wavemakers-synth.com
>
>
> > -----Original Message-----
> > From: ComputerVoltageSources@yahoogroups.com
> >
> >
> > > - Output gain & offset pots or fixed?
> >
> > Fixed at 10.625 volts full scale. 4 steps per semitone at one volt per
> > octave 12 bit.
> >
>