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Entry  Tue Sep 29 12:47:08 2009, Koji, Update, MZ, MZ unlocked 
    Reply  Tue Sep 29 18:21:41 2009, Koji, Update, MZ, MZ work done 
       Reply  Tue Sep 29 21:37:09 2009, rana, Update, MZ, MZ work done : some noise checking fsm.pdf
          Reply  Tue Sep 29 21:51:32 2009, Koji, Update, MZ, MZ work done : some noise checking 
       Reply  Tue Sep 29 22:51:20 2009, Koji, Update, MZ, Possible gain mis-calibration at other places (Re: MZ work done) 
Message ID: 2021     Entry time: Tue Sep 29 21:37:09 2009     In reply to: 2020     Reply to this: 2022
Author: rana 
Type: Update 
Category: MZ 
Subject: MZ work done : some noise checking 

Since we used to run with a gain slider setting of +15 dB on the MZ, I wanted to check that the new setting of +30dB was OK. It is.

To check it I turned it up and looked for some excess noise in the ISS or in the MC. There was none. I also set the input offset slider by unlocking the PMC and zeroing the mixer monitor readback. The new slider setting is -6.5V.

I don't know why we would need more gain on the MZ loop, but we can have some if we want it by turning up the gain before the servo (optical or RF). The attached plot shows the MC_F and ISS signals with the ISS loop on and off. There was no change in either of these spectra with the MZ gain high or low.

Attachment 1: fsm.pdf  60 kB  | Hide | Hide all
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