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Reports until 23:02, Friday 20 February 2015
H1 ISC
alexan.staley@LIGO.ORG - posted 23:02, Friday 20 February 2015 - last comment - 05:30, Saturday 21 February 2015(16840)
An attempt at DARM with more phase

Alexa, Sheila, Evan, Dan

Peter had noted that our suspension compenstation for the LSC DARM filter was different than the one used at LLO. In his plot LHO#16728 he had actually missed a Lead filter at 200 Hz (FM9) that we turn on once we are on RF DARM. See new sus compenstation comparison plot. Even with this lead filer on, we still do not have as much phase as Livingston.

Today, I loaded LLO's suspension compenstation filter into FM1 of LSC DARM. We tried enaging this for ALS DIFF but immediately saturared L3. Our next plan in attempt to acquire more phase margin is to develop a filter which can be engaged along with the lead filter (FM9) once we are on RF DARM with our original sus compensation filter (FM8), and see if this causes saturation. TBD.

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peter.fritschel@LIGO.ORG - 05:30, Saturday 21 February 2015 (16844)

Did you include the stopband (notch) filter for the violin mode fundamentals? If not, perhaps these were saturating L3?

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