[sdiy] DCO amplitude with filtered PWM

rsdio at audiobanshee.com rsdio at audiobanshee.com
Fri Aug 31 05:53:49 CEST 2018

Would you be willing to explain what you mean by “over compensating the integrator”?

Does that mean you cannot simultaneously output ramp and square?

Does your integrator run into saturation purposely?

Does your integrator charge or discharge during the reset?

I can almost imagine how you’re getting square by over compensating, but not PWM.


On Aug 30, 2018, at 8:46 PM, Declare Update <declareupdate at gmail.com> wrote:
> This core is indeed unipolar, and AC coupled after. In my case, I’m actually creating square and pwm shapes by over compensating the integrator, instead of the usual comparator, since everything is under tight control from the micro. my current scheme has the integrators reference (+ input of the op amp) fed by a DAC as well, so it’s quite flexible. switching to the much slower PWM scheme away from the very fast 12bit DACs on the spendy chips will limit its ability in that regard.
> Now I’m interested to see if the Juno 6 pulse width changes with wide bends from the bender or LFO. I’ll have to check it out. 
> Including the expo converter is seeming like a better idea with all of this in mind. sticking with the fancy chip and its “dank DACs” is feeling better, too :) These imaginary $0.50 DCOs taunt me so. 
> Cheers,
> Chris

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