[sdiy] DCO amplitude with filtered PWM

[Tom Wiltshire]

PWM is harmonically equivalent to detuned sawtooths. That this is true is demonstrated by the fact that one way to generate a PWM waveform is to mix a sawtooth and a ramp wave (e.g. inverted saw) and then tweak the relationship of the phases.

What you describe with the heavy uP control of the waveform generation sounds like where the later CEM chips like the 3396 finished up, although perhaps you’ve got even further in that direction.

Tom

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       Electric Druid
Synth & Stompbox DIY
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> On 31 Aug 2018, at 07:40, Declare Update <declareupdate at gmail.com> wrote:
> 
> I built this because I had a thought a while
> back that I could simulate detuned sawtooths with one integrator if I could control slope, reset rate, and reset level of a DCO with an MCU. I whipped it up in max to confirm it works, but haven’t gotten around to trying that specifically in the hardware, heh. I’ve found that this much flexibility is not necessary in most cases, though it does let me generate just about any waveform I’m patient enough to work out.