[time-nuts] Re: Why do have OCXO a Vref output? (was: help reviving Trimble UCCM-LPS GPSDO)

[Richard (Rick) Karlquist]

When I designed the HP E1938A, I put a 2.5V reference IC inside the oven 
and brought out both terminals of it.  This was intended to provide a 
reference voltage to the external DAC that generated the tuning voltage 
for the loop that locked it loosely to GPS.  It had its own return path 
that was not only independent of the oven but the oscillator as well.
The oven in the E1938A had a thermal gain to the crystal in the 100's of 
thousands.  The thermal gain to the reference was no where near this 
value, but still very substantial compared to anything on the outside.

Rick N6RK