[sdiy] Active VCO temp compensation

[George Hearn]

I'd like to modify my polysynth design to use active temperature
compensation by making the VCO's output a temperature reference voltage that
has a TC of 3300ppm/c.  This would then be used to derive the DAC reference
voltage in order to compensate for the VCO exponential converter temperature
drift.  I would like to do this by using a MAT04 quad matched pair or
LM3046, using two transistors to make the exponential converter and somehow
use the others to generate a voltage proportional to Vt.  Does anyone have
any ideas?  The CEM3374 had this arrangement and it was successfully
employed in the Oberheim XPander and Matrix 12.  Regards, George