Daniel, Craig, Dhruva, Vicky

Took some TFs and in-loop spectra of the CLF and LO loops today.

Doing this phase noise investigation because from Dhruva's SQZ alignments yesterday, LHO:66877, the "LO Loops Adjusted" meant we 1) increased common boost several dB, 2) turned off all LO_OMC boosts, and gained ~0.5 dB SQZ (140/140 lime green vs 140/140 dark purple from 66877). However, this meant we had NO CMB boosts in the LO_OMC or CLF servos! Making their transfer functions totally flat? So, if this is giving us more sqz, is turning off all boosts giving us somehow an improved phase noise scenario? Or something else? Notable changes from last time we ran SQZ TF's (Aug 2022, 64581) are we have lower CLF power now, so maybe sensing noise related? Craig is helping us with his SR785 scripts, we are documenting our usage the code here for future reference.

CLF_RF6    RFMON @ -29.2.

CLF_tf . calibration = 660mVpk-pk / (2 rad) = 330mV/rad. +27dB common, +6dB fast, 1 and 2 common boosts

clf spectrum.txt : saved with multiple FFT bin widths, 400 Hz, 1.6kHz, 25kHz, 100kHz

OMC_TRANS_RF3    RFMON @ -18.5.

LO_tf . calibration = 500mVpk-pk / (2rad) = 250mV/rad. -2dB common, +0dB fast, 1 and 2 common boosts

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Using Craig's psl SR785 scripts to take these measurements. See LHO:64204 to get started.

Had to do this once to get the "quick_psd" function working on my cds account: conda init bash

To get noise spectrum data at many BWs:

• cd /ligo/gitcommon/psl_measurements/templates
• ./run_all_sr785_spectra_templates_sqzfast.sh 10.22.10.31 10 /ligo/gitcommon/psl_measurements/data/sqz_loops/garbage_test

To view a single .txt data file:

• cd /ligo/gitcommon/psl_measurements/data/sqz_loops/
• python /ligo/gitcommon/psl_measurements/code/quick_spec_plot.py garbage_test _102p4kHz_19-01-2023_121747.txt
  • this generates .pdf of a data .txt file
• quick_psd garbage_test _102p4kHz_19-01-2023_121747.txt  (in the directory with the txt file)
  • this pulls up GUI of a data .txt file
• quick_psd garbage_test*
  • this pulls up a GUI with all data .txt files together

To stitch spectra from many BWs together:

• python /ligo/gitcommon/psl_measurements/code/multi_spec_plot.py garbage_test*.txt --title "garbage stich" --stitch

To check stitched results:

• quick_psd clf_1_boost_stitched_spectra.txt clf_2_boost_stitched_spectra.txt

For example, with our morning data we manually collected, I did:

• cd (folder w/saved data .txt files)
• python /ligo/gitcommon/psl_measurements/code/multi_spec_plot.py lo_spec*1boost*.txt --title "LO 1 boost" --stitch
• python /ligo/gitcommon/psl_measurements/code/multi_spec_plot.py lo_spec*2boost*.txt --title "LO 2 boost" --stitch
  • at the end, the script prints e.g. "ASD file saved at
    /ligo/home/victoriaa.xu/Downloads/011922_clf_lo_loops/lo_2_boost_stitched_spectra.txt"
• quick_psd lo_1_boost_stitched_spectra.txt lo_2_boost_stitched_spectra.txt
  • running "quick_psd" to pull up the stitched spectra