Fast VCOs/V->F converters

[Martin Czech]

> I did the math, and perhaps its even correct! (; :
> 
SNIPPED A NICE ERROR ESTIMATION.

Perhaps the pll approach could work without too much artefacts.  If you
make a decent hf-vco that has only an error of about some semitones, you
could compare that to a dco with the exact frequency. Assuming 0.083V per
semitone, the corrective voltage has only to be , say , 200mV maximum.
Ie. there is a closed loop regulation, but a very weak one, just enough
to pull the hf-vco to the exact value. The normal sproiiiing artefact
comes from wide range plls, with strong feedback. This is not neccessary
if the hf-vco is allmost correct.

m.c.