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Entry  Mon Jul 11 11:56:40 2022, he Yehonathan, Update, BHD, MICH AS55 noise budget Control_Diagram.pdfMICH_AS55_Noise_Budget.pdf
    Reply  Tue Jul 12 09:14:50 2022, rana, Update, BHD, MICH AS55 noise budget 
       Reply  Wed Jul 13 10:54:39 2022, Yehonathan, Update, BHD, MICH AS55 noise budget BS_MICH_ACtuation_Calibration.pdfMICH_AS55_Model_Measurement_Comparison.pdfMICH_AS55_Noise_Budget.pdf
          Reply  Wed Jul 13 13:30:48 2022, Yehonathan, Update, BHD, add Laser RIN to MICH budget 
             Reply  Mon Jul 18 16:49:57 2022, Yehonathan, Update, BHD, add Laser RIN to MICH budget Laser_RIN.pdfMICH_AS55_Noise_Budget.pdf
                Reply  Mon Jul 18 18:33:38 2022, Koji, Update, BHD, add Laser RIN to MICH budget 
Message ID: 17015     Entry time: Mon Jul 18 18:33:38 2022     In reply to: 17013
Author: Koji 
Type: Update 
Category: BHD 
Subject: add Laser RIN to MICH budget 

You should measure the coupling by noise injection. Noise budgeting does not need any modeling:

1) Measure the power spectrum density of the target signal (i.e. DARM) and the source noise (i.e. RIN this case)

2) Calibrate both using a calibration peak to convert 1) into the physical units (m/rtHz, 1/rtHz, etc)

3) Measure the transfer function from source to target using the noise injection. (i.e. RIN injection this case and look at the injection to RIN and injection to DARM)

4) Measure open-loop transfer functions if necessary. (i.e. DARM control open-loop transfer function to convert the error signal into the free running noise level)

Primarily, these are measured noise levels and noise couplings there is no room to involve a model there.
Once the noise budget was done, you can compare it with the model and say "the coupling is big/small/comparable".
 

Also, why don't you use C1:MC_TRANS_SUMFILT_IN1_DQ instead? Your _OUT signal seems affected by the bunch of comb notch filters to artificially remove the 60Hz harmonics. It's not a fair RIN measurement.

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