[sdiy] Midi2CV accuracy(was MIDI2CV alternatives)

[Paul Maddox]

Scott,

> Not being an expo user, but out of curiosity, I have a question about expo
> CV output MIDI2CV converters:  Does each bit combination represent one
> semitone?  I.e., when the circuit is properly scaled, does each increment
to
> the DAC input register coincide with 1/12 of a volt increase in output?
If
> so, I can understand why DAC accuracy and consistency is important.

it depends, if you have a 7bit DAC, and you're using MIDI, then yes, each
bit is one semitone.
If you use 8bits, then each bit is half a semitone, using 12bits gives you 1
bit = 1/32 of a semitone.
Most DACs show their non-linearity in bits, most are around +/-1 Bit of
error, So, the more bits you have, the smaller the error, Even if you never
use the lower bits.
A 16bit Dac gives you 1/256th of a semitone per bit.

Paul