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Entry  Tue Dec 10 15:13:55 2013, Koji, Update, IOO, IMC servo inspection 
    Reply  Thu Dec 12 14:57:01 2013, Koji, Update, IOO, IMC servo inspection OLTF_IMC.pdfAOTF_IMC.pdf131209.zip
       Reply  Fri Dec 13 18:03:00 2013, Den, Update, IOO, common mode servo CM_OL.pdfCM_CL.pdf
          Reply  Fri Dec 13 23:07:04 2013, Koji, Update, IOO, common mode servo 
          Reply  Sat Dec 14 11:56:54 2013, rana, Update, LSC, common mode servo 
             Reply  Sat Dec 14 14:21:46 2013, Den, Update, LSC, common mode servo 
Message ID: 9468     Entry time: Fri Dec 13 18:03:00 2013     In reply to: 9457     Reply to this: 9470   9472
Author: Den 
Type: Update 
Category: IOO 
Subject: common mode servo 


Well, let's see how the CM servo can handle this.
The key point here is that we have enough data to start the design of the CM servo.

 It seems to me that current design of the common mode servo is already fine. Attached plots show common mode open and closed loop transfer function.

Frequency response of the servo is taken from the document D040180. I assumed coupled cavity pole to be ~100 Hz.

The only question is if our EOM has enough range. Boost 2 increases noise injection by 10 dB in the frequency range 20-50 kHz. Boost 3 has even higher factor.

Attachment 1: CM_OL.pdf  79 kB  | Hide | Hide all
Attachment 2: CM_CL.pdf  86 kB  | Hide | Hide all
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