V/Oct >> Hz/V converter circuit?

[Magnus Danielson]

From: "||| Philip Pilgrim |||" <thelab at sprint.ca>
Subject: V/Oct >> Hz/V converter circuit?
Date: Sat, 15 Jan 2000 10:28:36 -0400

Hi Philip!

> I just chopped a CS-10 and am about to make it "modular"  I would like to
> convert it to v/oct. Is there a simple front end circuit I could install?
> Couldn't find anything on the net :(

Take the expo guts from some v/oct VCO and feed the current output into an
op-amp with a resistor from output to (-) input. The current output should hit
this (-) input. Now, take the (+) and hook it to ground. The output would now
become the Hz/V. Change the feedback resistor to scale the Hz/V.

This treatment can be done to the ASM-1 VCO for instance, but is equalently
easy to do to most others since many such VCOs consists of these oct/V to
Hz/A converters. The opamp just convert Hz/A into Hz/V by doing a current to
voltage conversion.

Cheers,
Magnus