Bruce Griffiths provided this circuit:
I made a simple change by adding an OPAMP (U2B) to invert the output so a positive swing in EFC would result in a corresponding swing
of the EFC translation voltage.
Without it, the EFC swing would be inverted.
Again, for simulation purposes, I used a LT1208 OPAMP but in real life I would use a device with better specs.
Also, in real life, VREF (+5V) would be provided my an AD586 (preferably an AD586MNZ).
The Fury ground offset has almost no effect on the OCXO_EFC, as would be expected.
I did not include any output waveforms since they are just DC values.
The note box explains the values needed for different EFC Translation Voltages.
Here is the schematic: