SV: [sdiy] Mopho modulation DAC configuration, update rate, etc

[karl dalen]

> That's not so bad. Gives him a theoretical top end of about
> 500Hz for modulation frequencies. But the LFOs on his stuff
> go only go up to Middle C at 261Hz, so he's keeping it all
> on the safe side.
> He might mean that the modulations within the dsPIC voice
> processor (e.g. the ones that never leave the digital
> domain) are calculated at a higher rate than the DAC runs
> at.

yes but he have said that in context of the *slow*
analog side, which of course are not true.

However he might have reffed to CV slew circuit which
will put up a Bw limit on update rates.

It's kind of peculiar, he uses 16 bit DAC whit rather
poor INL and then slews of the steps by a RC net??

The Pic are fast enough to generate modulation without
skipping bits.
 
> For example, I did some code for a dsPIC dual oscillator.
> It only read its CV inputs at about 5KHz, which puts a limit
> on the modulation frequency, but it could still do FM
> effects because you could send one oscillator to the other's
> phase input digitally at the full sample rate.

Offcourse but there are basically no *modulation* frequency
limit within the PA397, it can go into audio frequency range
if one designs it in.

KD



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