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Entry  Mon Sep 9 20:46:28 2013, Masayuki, Update, LSC, MICH calbration 
    Reply  Tue Sep 10 17:35:50 2013, Masayuki, Manasa, Update, LSC, MICH calbration MICH_calib_loops.pngOLTF_MICHDC.pngMICH_DC_resp.pngMICH_RF_resp.pngMICH_free_noise.png
       Reply  Thu Sep 12 23:36:25 2013, Masayuki, Update, LSC, MICH calbration BSsus.PNGITMXsus.PNGITMY.PNGfree_running.PNG
          Reply  Fri Sep 13 19:22:01 2013, Masayuki, Update, LSC, MICH calbration noise.PNG
             Reply  Mon Sep 16 14:11:47 2013, rana, Update, LSC, MICH calbration Screen_Shot_2013-09-16_at_2.10.31_PM.pngScreen_Shot_2013-09-16_at_2.18.47_PM.png
                Reply  Tue Sep 17 00:50:42 2013, Masayuki, Update, LSC, MICH calbration noise.PNG
Message ID: 9128     Entry time: Fri Sep 13 19:22:01 2013     In reply to: 9127     Reply to this: 9131
Author: Masayuki 
Type: Update 
Category: LSC 
Subject: MICH calbration 

 

 I made sure the yesterday's result was collect. I measured not only the error signal but also the feedback signal. And I compared those signals and measured the TF in order to confirm my servo filter model is not wrong.

The reason of dip at low frequency region is maybe the coherence of the ground motion. The ITMX and ITMY suspensions are put close. If ground motion has coherence, the mirrors move in common mode. That will suppress the free running noise. The attachment is the free running noise of Sep 13rd and Sep 12nd.

Attachment 1: noise.PNG  40 kB  | Hide | Hide all
noise.PNG
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