I guess if you have a frequency counter with a GPIB interface or a simple flip-flop XOR based phase/frequency discriminator, you can feed the output to a 3113 and use at as an input to a slow EPICS PID to bring the beat frequency to within range.
Actually, we need a frequency discriminator for the Green Locking so it might be good to brainstorm about this with Aidan and Koji. |