[sdiy] midi 2 cv

[Paul Maddox]

Michiel,

> I was observing this topic, and while reading I was questioning myself
what
> the importance of bits actually are in this DAC of a Midi2CV converter.
> Would a higher bit rate mean that more notes are detected? So that a
larger
> keyboard can be used?

ok, somethings to understand,
By BITRATE I assume you mean the refresh of the DACs?
the faster they update, in theory the less notes/data they will miss, but
given MIDI isn't that fast, this is only valid to a point.

> If I´m not mistaking, I find that with 8 bits allready 256/2 = 128(on+off)
> logical values of information can be "read", and that should be more than
> enough for a simple keyboard.. or am I thinking too simple/in the wrong
way?

no, you're right, BUT the catch is that DACs arent that linear or stable,
for example a typical 8Bit DAC will have a linearity of 1LSB, this means the
value could change by 1LSB with each change in value..
If you goto something like a 16Bit DAC the same applies, but becuase we're
talking about 16Bits (we move the data we want into the top 7 bits) then
error (1LSB) is much much smaller (256 times smaller)...

The other thing to remember is that some controllers (Pitch bend for
example) actually use TWO data bytes (of 7 bits) and have a 14bit
resoloution..

Paul