40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  PSL  Not logged in ELOG logo
Entry  Thu May 23 15:45:48 2019, anchal, DailyProgress, FSS, Oscillations in North FSS Mixer Channel and power NorthCavFSSOsc.pdf
    Reply  Thu May 23 15:56:22 2019, awade, DailyProgress, FSS, Oscillations in North FSS Mixer Channel and power 
Message ID: 2351     Entry time: Thu May 23 15:56:22 2019     In reply to: 2350
Author: awade 
Type: DailyProgress 
Category: FSS 
Subject: Oscillations in North FSS Mixer Channel and power 

~7kHz would be close to the cross over frequency wouldn't it? Maybe also see if you can capture PZT and EOM actuation signals in the same sweep (at their full bandwidth, i.e. careful of the montors filtering things off at higher frequencies).   

Also, an aside: you might want to also tar and attach data + plotting to elog as url links rot over time.

Quote:

After the vacumCans are heated, I aligned the north cavity again today to about 60% mode matching. however, I'm seeing a weird oscillation in the mixer channel of FSS board which is very big (5 Vpp) and is happening alongside a large power fluctuation in transmitted light. See attached plot from oscilloscope of reflected DC level and the micer channel from FSS. The repition rate of the oscillations make this a 7.35 kHz noise. I have never seen this before. Further, these oscillations are completely unaffected from chaning COM gain or the Fast gain in the FSS path. Comments required.

Code and Data

 

ELOG V3.1.3-