Polysix VCOs (was: Tempco)

Haible Juergen Juergen.Haible at nbgm.siemens.de
Mon May 18 12:54:40 CEST 1998


	>The Poly Six (IIRC) has linear oscillators driven by a dac with an
	>exponential convertor on it's output that's multiplexed between all
the
	>oscillators. Maybe that's a better solution for a multi-osc synth
than
	>doing the exponential conversion digitally, then introducing an
error at
	>the dac.

The P6 uses this trick (multiplexed expo converter) in combination
with another one: limited VCO frequency range. As you choose different
VCO footage, the VCO frequency is not changed, but frequency dividers
are switched on and off. Look at how they produce frequency divided
saw waves - very interesting stuff.
If memory serves, the Trident's VCOs are similar. Good for stability
(and for that typical rich linear VCO beating), but bad if you want sync
or crossmodulation.

JH.




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