[sdiy] 2164 Expo VCO tracking

[David G. Dixon]

> One technique is to place the board in a styrofoam cooler to avoid air
> current effects. You can also place a heater inside and/or place the
> cooler in a refrigerator (take off the lid for about an hour) or outside.
> When using these heating or cooling devices, you have to allow the
> temperature to stabilize before making readings.
> 
> Even when calibrating our state of the art VCO, one has to be carefull not
> to breathe on the PCA to avoid differential heating of the various temp
> sensitive components.

I guess I'm just not that concerned about small temperature fluctuations.
My VCO was designed to be as stable with temperature as it can be, and if I
can get decent tracking/tuning without taking any special precautions, then
I'm happy.

In any case, temperature stability is not the problem.  Log conformance
above 0V is.