Nutsinee Daniel
Sometime back Marc implemented the changes of ECR E1800041 to the spare VCXO D1600500 with S/N S1700238. We then promptly forgot about it, until we encountered a calibration discrepancy in the VCXO drive that indicated that we were missing a factor of 1/25 in gain. Today, we swapped the current unit S1700237 with the spare, which eliminates the 1.6Hz/40Hz pole-zero pair and uses an AT cut crystal. As an added benefit we now need a lot less gain in the CLF CM board and the DAQ readbacks no longer overflow.
The output of this VCXO goes to the bottom pre-amp which drives AOM2 (AA Opto Electronic MT200). There's a 10dB attenuator at the input. We gain a couple of extra dB but we should still be within range of max power allowed to drive that AOM (previously we had 6dB attenuator here, that would have been marginal).