Re(2): V/Oct >> Hz/V converter circuit?

[jhaible]

> 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.

I've built one recently, have not drawn schematics, but it's exactly as
Magnus
describes. What I want to add: Use an opamp with low offset voltage for
this,
as you're always fighting errors of low frequency tracking in linear VCOs.
This is important for *all*stages that follow the expo converter, like glide
circuits.
Good opamp choices are LF411 or OP-07.

JH.