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Entry  Thu May 16 04:46:37 2013, Jenne, Update, LSC, Kiwamu's sensing matrix measurement script revived 
    Reply  Thu May 16 23:48:39 2013, Jenne, Update, LSC, Kiwamu's sensing matrix measurement script revived 
       Reply  Mon May 20 17:49:36 2013, Jenne, Update, LSC, PRMI sensing matrix - not high quality data PRMIsensMatQuickAnalysis.m.gz
          Reply  Mon May 20 18:47:47 2013, Koji, Update, LSC, PRMI sensing matrix - not high quality data 
             Reply  Tue May 21 14:48:08 2013, Jenne, Update, LSC, PRMI sensing matrix - not high quality data 
       Reply  Mon May 20 18:50:22 2013, Jenne, Update, LSC, Kiwamu's sensing matrix measurement script revived 
          Reply  Tue May 21 18:22:18 2013, Jenne, Update, LSC, Sensing matrix scripts modified to include actuator calibration 
             Reply  Wed May 22 00:08:19 2013, Koji, Update, LSC, Sensing matrix scripts modified to include actuator calibration 
                Reply  Wed May 22 18:24:19 2013, Jenne, Update, SUS, Violin mode survey 
                Reply  Wed May 22 20:50:26 2013, Jenne, Update, LSC, Sensing matrix scripts don't calculate correctly 
                   Reply  Thu May 23 14:45:08 2013, Jenne, Update, LSC, Sensing matrix scripts calculations make more sense now SensMat_JenneMeas_23May2013.pngSensMat_KojiMeas_23May2013.png
                      Reply  Thu May 23 21:45:51 2013, Jenne, Update, LSC, Sensing matrix scripts now check for lockloss 
                Reply  Thu May 23 19:09:15 2013, Jenne, Update, LSC, Sensing matrix scripts modified to include actuator calibration SensMat_21May2013.png
          Reply  Wed May 22 18:07:36 2013, Jenne, Update, LSC, Kiwamu's sensing matrix measurement script revived 
             Reply  Thu May 23 00:49:13 2013, Jenne, Update, LSC, LSC filters loaded 
Message ID: 8621     Entry time: Wed May 22 20:50:26 2013     In reply to: 8611     Reply to this: 8630
Author: Jenne 
Type: Update 
Category: LSC 
Subject: Sensing matrix scripts don't calculate correctly 

I am trying to re-analyze the data that Koji took last night.  

I think that my script is just pulling out the I and Q data for each port, and each degree of freedom, calculating the magnitude from sqrt( I**2 + Q**2 ) and the phase from atan2( I / Q ).  No calibration.

If I print out the results, I get:

Sensing Matrix, units = cts/ct, phase in degrees
 
            MICH Mag   MICH Phase    PRCL Mag   PRCL Phase  
AS55_I      1.627E-02   62.063        4.189E-03   68.344       
AS55_Q      2.073E-02  -105.353        1.983E-02   66.361       
REFL11_I    8.165E+02  -112.624        2.441E+00   77.911       
REFL11_Q    2.712E+02  -112.650        7.065E-01  -127.093       
REFL33_I    8.028E+00  -112.154        6.282E-02   70.990
       

REFL33_Q    5.490E-02  -165.912        9.908E-03   61.269       

REFL55_I    8.347E+00  -112.085        2.146E-02   78.928       
REFL55_Q    3.003E-01  -151.652        7.924E-02   87.153
 

If, however, I take the raw values that are stored in the data file, for one row (say, REFL33_Q) and calculate by hand (same formulas), I get different results:

            MICH Mag   MICH Phase    PRCL Mag   PRCL Phase  
REFL33_Q    9.9E-03    28.89         5.46E-02   -103.8

Contrast that with Koji's uncalibrated transfer function result from elog 8611:

            MICH Mag    MICH Phase    PRCL Mag     PRCL Phase  
REFL33Q     1.8665e-5   71.1204      
1.6310e-4    -141.73

 

I am currently confused, and need to re-look at my script, as well as make sure I am actually measuring the things I think I am.

EDIT:  This has been fixed, in that my 2 calculations agree with one another.  I have crossed out the incorrect numbers, and put correct numbers below.  I still don't agree with Koji, but at least I agree with myself. 

The phase issue:  I needed to calculate the phase with "ATAN2(I,Q)", which I did when I calculated by hand, but the script had "atan2(Q,I)".  This has been fixed. 

The magnitude issue:  They match, but my "pretty print" script labels MICH as PRCL, and vice versa.  Doh.

Corrected values:

Sensing Matrix, units = cts/ct, phase in degrees
 
            PRCL Mag   PRCL Phase    MICH Mag   MICH Phase  
AS55_I      1.627E-02    27.937      4.189E-03    21.656     
AS55_Q      2.073E-02  -164.647      1.983E-02    23.639     
REFL11_I    8.165E+02  -157.376      2.441E+00    12.089     
REFL11_Q    2.712E+02  -157.350      7.065E-01  -142.907     
REFL33_I    8.028E+00  -157.846      6.282E-02    19.010     
REFL33_Q    5.490E-02  -104.088      9.908E-03    28.731     
REFL55_I    8.347E+00  -157.915      2.146E-02    11.072     
REFL55_Q    3.003E-01  -118.348      7.924E-02     2.847 

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