[sdiy] frequency counter

[Antti Huovilainen]

On Sun, 25 Oct 2009, cheater cheater wrote:

> I'm not sure if this has been answered before, but what bit depth *do*
> you need exactly in pitch CVs?

Assuming a ten (-5..+5) octave range, the step between adjacent
values will be

47 cents for 8 bit dac
12 cents for 10 bit dac
2.9 cents for 12 bit dac
0.7 cents for 14 bit dac
0.2 cents for 16 bit dac

I'd say you need at least 12 bits. Your overall worst case error is going 
to be larger because the integral nonlinearity and gain error of the DAC 
are worse than 1 lsb.

> Can a chain of AD->uC->DA inserted after the expo help with high
> frequency performance, by introducing correction offsets?

No. It will be too slow. If you want to use MCU to adjust for high freq 
tracking errors, it's better to incorporate that into the master pitch CV 
dac. Any tracking error is unlikely to matter in the modulation.

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
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