SV: [sdiy] QVCO schemo up

[JH.]

> Using  the linearizing diodes ~guarantees~
> that you will have big offset troubles. The simulation
> can be trimmed easily to remove them.
> 
> Probably the real one will work as well.


The stupid diode biasing system of the 13700 forces
the common mode input voltage to some positive value,
which means the resistor that feeds the input signal
draws a hefty bias current, and unbalances the input.
So you have to set the offset trimmer to an odd value
even if you'd have a perfect OTA.

JH.