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Message ID: 15343     Entry time: Fri May 22 01:43:18 2020
Author: gautam 
Type: Update 
Category: Electronics 
Subject: RF electronics trouble 

To test a hypothesis, I have left the PSL shutter closed. I notice significant glitches in the dark electronics offsets on all the 11 MHz photodiode I/Q demodulated input channels, which appear coherent. These are non-negligible in magnitude - for now they are uncalibrated in cts, but for an estimate, the POX11 channel shows a shift of ~20 cts (~200uV at the input to the whitening board), while the PDH fringe is ~200 cts pk2pk. A first look is in Attachment #1. The fact that it's in all the 11 MHz channels makes me suspect something in the RF chain, maybe some amplifier? I'll open the shutter tomorrow.

Attachment 1: RFPDglitches.png  331 kB  Uploaded Fri May 22 02:58:48 2020  | Hide | Hide all
RFPDglitches.png
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