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Entry  Tue Feb 28 12:00:54 2012, kiwamu, Update, LSC, installed anti-whitening filters 
    Reply  Tue Feb 28 15:48:32 2012, kiwamu, Update, LSC, installed anti-whitening filters 
    Reply  Tue Feb 28 16:39:25 2012, kiwamu, Update, LSC, MICH and PRCL signals in a simulation REFL11_PRMI.pngREFL55_PRMI.png
       Reply  Tue Feb 28 16:44:56 2012, rana, Update, LSC, MICH and PRCL signals in a simulation 
Message ID: 6334     Entry time: Tue Feb 28 16:39:25 2012     In reply to: 6330     Reply to this: 6335
Author: kiwamu 
Type: Update 
Category: LSC 
Subject: MICH and PRCL signals in a simulation 

I briefly ran a Optickle code to see how the PRC macroscopic length screws up the sensing matrix in the PRMI configuration.

Especially I focused on the optimum demodulation phases for the MICH and PRCL signals to see how well they are separated in different PRC length configuration.

It seems that the demod phases for MICH and PRCL are always nicely separated by approximately 90 degree regardless of how long the PRC macroscopic length is.

If this is true, how can we have such a strange sensing matrix ??

 


(Simulation results)

 The plots below show the simulation results. The x-axis is the macroscopic length of PRC in a range from 6.3 meter to 7.3 meter.
The y-axis is the optimum demodulation phases for MICH (blue) and PRCL (black).
The red line is the difference between the MICH and PRCL demodulation phases.
The left plot is for the REFL11 signals and the right plot is for the REFL55 signals.
When the difference is 90 degree, it means we can nicely separate the signals (i.e. REFL11I for PRCL and REFL11Q for MICH).
Obviously they are always nicely separated by ~ 90 deg.

 

REFL11_PRMI.pngREFL55_PRMI.png

Quote from #6330
The lock of the PRMI doesn't look healthy, especially the sensing matrix doesn't make sense at all (#6283).
A very staring thing in the sensing matrix is that the REFL11 and REFL55 didn't show the 90 degree separation between MICH and PRCL.

 

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