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Message ID: 2420     Entry time: Tue Dec 15 21:39:34 2009
Author: Alberto 
Type: Update 
Category: ABSL 
Subject: brief summary of this afternoon's measurements 
I took measurements of the open loop gain of the AbsL PLL with the old Universal PDH Box.
I Also measured the filter shape of both the new and the old PDH box.
I'm going to plot the results in a nice form tomorrow morning.
For who's interested, the PLL UGF was at 10KHz.
I can't lock the PLL with the new PDH box. Measuring its filter's shape, as suggested by Koji, I found out that it differs from the old one. That despite the fact that the two boxes should share the same circuit schematic. O,r at least, that is what it looks like from the schematics in the DCC.
I need to understand whether that is intentional and, if that was the case, what kind of use  Rich Abbott designed it for.
Tomorrow I'm going to post in the elog the filter's transfer functions too.
Before leaving the lab I closed the auxiliary laser's mechanical shutter.
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