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Entry  Fri Apr 24 03:57:30 2009, Yoichi, Update, Locking, DARM demod phase 
    Reply  Fri Apr 24 04:38:49 2009, Yoichi, Update, Locking, DARM demod phase 
       Reply  Fri Apr 24 11:34:32 2009, rob, Update, Locking, DARM demod phase darm_phase_rotate.png
          Reply  Fri Apr 24 17:26:57 2009, Yoichi, Update, Locking, DARM demod phase 
Message ID: 1515     Entry time: Fri Apr 24 04:38:49 2009     In reply to: 1514     Reply to this: 1516
Author: Yoichi 
Type: Update 
Category: Locking 
Subject: DARM demod phase 

Quote:
Tonight, I was able to go up to arm power = 40 by tweaking the DARM demodulation phase.
I think the DARM loop became unstable because the demodulation phase was not right and the error signal contained some junk from I-phase.
I did not do any sophisticated demodulation phase optimization. Rather I just tweaked the phase so that the dark port image becomes stable.
I will do more careful demodulation phase tuning next time.


In the next try, I was actually able to go up to arm power = 70 stably.
At this power level we are ready for the RF CARM hand off.
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