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Entry  Mon Sep 1 19:23:17 2008, Yoichi, Configuration, PSL, FSS on an auxiliary loop 
    Reply  Tue Sep 2 09:58:42 2008, Yoichi, Configuration, PSL, FSS on an auxiliary loop 
Message ID: 908     Entry time: Mon Sep 1 19:23:17 2008     Reply to this: 910
Author: Yoichi 
Type: Configuration 
Category: PSL 
Subject: FSS on an auxiliary loop 
Summary: The FSS is now temporarily disabled. Naturally, the MC won't lock. I will fix it tomorrow morning.

Today, I did the 4th item of my TO DO list.
Using a mini-circuit mixer and two SR560s, I constructed an auxiliary servo loop for the reference cavity.
With this loop, I was able to lock the reference cavity without using the FSS box.
By locking the reference cavity with this auxiliary servo, I was able to measure the PC path transfer function.
I will post the analyzed results later.

I borrowed the PD RF and the LO signals from the main FSS loop by power splitters. Therefore, the gain of the main FSS loop
is now about 3dB low. I tried to compensate it by increasing the EOM modulation depth, but the PC path is still a bit noisy.
Probably the already too low LO power is now seriously low (the LO power cannot be changed from EPICS).
Because I did not want to leave the PC path with large output overnight (it will heat up the PA85, and might cause damage, though unlikely),
I disabled the FSS for now.
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