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Entry  Tue Nov 11 03:48:46 2014, Jenne, Update, LSC, 3f DRMI SensMatMeas_10Nov2014_DRMI.pngSensMatMeas_10Nov2014_PRMI.png
    Reply  Tue Nov 11 21:41:09 2014, Koji, Update, LSC, 3f DRMI sensing mat DRMI_radar.pdf
       Reply  Wed Nov 12 03:22:23 2014, Jenne, Update, LSC, 3f DRMI sensing mat 8x
Message ID: 10701     Entry time: Wed Nov 12 03:22:23 2014     In reply to: 10698
Author: Jenne 
Type: Update 
Category: LSC 
Subject: 3f DRMI sensing mat 

Koji pointed out something to me that I think he had told me ages ago, and Rana alluded to last night:  Since I'm not tuning my "demod phase" for the sensing matrix lockins, unless I happened to get very lucky, I was throwing away most of the signal.  Lame.  

So, now the magnitude is sqrt(real^2 + imag^2), where real and imag here are the I and Q outputs of the lockin demodulator, after the 0.1Hz lowpass.  (I put in the low pass into all of the Q filter banks).  To keep the signs consistent, I did do a rough tuning of those angles, so that I can use the sign of the real part as the sign of my signal.  When I was PRMI locked, I set the phase for all things acutated by MICH to be 79deg, all things actuated by PRCL to be 20 deg, and when DRMI locked set all things SRCL to be 50deg. 

After doing this, the phases of my sensing matrix output matches Koji's careful analyses.  I don't know where the W/ct numbers I was using came from (I don't think I made them up out of the blue, but I didn't document where they're from, so I need to remeasure them).  Anyhow, for now I have 1's in the calibration screen for the W/ct calibration for all PDs, so my sensing matrices are coming out in cts/m, which is the same unit that Koji's analysis is in. (Plot for comparing to Koji is at end of entry).

While reducing the CARM offset, I left the sensing matrix lines on, and watched how they evolved.  The phases don't seem to change all that much, but the magnitudes start to decrease as I increase the arm power.

For this screenshot, the left plot is the phases of the sensing matrix elements (all the REFL signals, MICH and PRCL), and the right plot is the magnitudes of those same elements.  Also plotted is the TRX power, as a proxy for CARM offset.  The y-scale for the TRX trace is 0-15.  The y-scale for all the phases is -360 to +360.  The y-scale of the magnitude traces are each one decade, on a log scale.

SensMatVsPower_UpToArms10.png

Bonus plot, same situation, but the next lock held for 20 minutes at arm powers of 8.  We don't know why we lost lock (none of the loops were oscillating, that I could see in the lockloss plot).

PRMI_arms8_20minutes.png


Here are some individual sensing matrix plots, for a single lock stretch, at various times.  One thing that you can see in the striptool screenshots that I don't know yet how to deal with for the radar plots is the error bars when the phase flips around by 360 degrees.  Anyhow, the errors in the phases certainly aren't as big as the error boxes make them look.

PRMI just locked, CARM offset about 3nm, CARM and DARM on ALS comm and diff, arm powers below 1:

SensMatMeas_11Nov2014_PRMIarms_ArmPowSmall.png

PRMI still on REFL33 I&Q, CARM and DARM both on DC transmissions, arm powers about 4:

SensMatMeas_11Nov2014_PRMIarms_ArmPow3pt8.png

CARM offset reduced further, arm powers about 6:

SensMatMeas_11Nov2014_PRMIarms_ArmPow6.png

CARM offset reduced even more, arm powers about 7:

SensMatMeas_11Nov2014_PRMIarms_ArmPow7.png


For this plot for comparing with Koji's analysis, I had not yet put 1's in the calibration screen, so this is still in "W"/m, where "W" is meant to indicate that I don't really know the calibration at all.  What is good to see though is that the angles agree very well with Koji's analysis, even though he was analyzing data from yesterday, and this data was taken today.  This sensing matrix is DRMI-only (no arms), 1f locking.

SensMatMeas_11Nov2014_DRMI_fixedMags.png

Bonus plot, PRMI-only sensing matrix, with PRMI held using REFL 33 I&Q:

SensMatMeas_11Nov2014_PRMI_fixedMags.png

 

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