pitch question

[Paolo Predonzani]

> > 
> > does anyone know if an 8bit ADC/DAC is enough for digitizing a pot
> > (e.g. pitch CV) on a modular ?
> 
> It depends on how much you like the sound of stairstepping when you turn 
> a pot.  There are a lot of synths w/ 8 bit control voltage routing.  The 
> Jupiter 6 is 7 bits, and the PAIA Proteus is only 4 bits.  Some go higher 
> - later Jupiter 8's have 14 bits.  So, 8 bit is pretty standard.
> 
> I wouldn't want less than 12 bits, myself...
> 
12 bits are enough for the DAC. If you want to sweep the audio
range (3 decades = 10 octaves), 12 bits give you a 3 cents pitch resolution.

For the ADC, I would suggest 2 pots: one for halftone intonation, the other
for fine tuning with limited range. They both require 7 bits. An 8 bit ADC
with multiplexed inputs is a good solution.
In any case, put a >100nF capacitor at the output of each controlled pot.
It will limit the noise bandwidth and make the sampled values more
stable and reliable.
 

-- 
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| Paolo Predonzani  |  email: predo at dist.dist.unige.it |
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