40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Message ID: 5726     Entry time: Fri Oct 21 16:59:14 2011
Author: Katrin 
Type: Update 
Category: Green Locking 
Subject: YARM PDH box broken 

I could not improve the locking. So, I checked the transfer function of the PDH box again. The transfer function looks okay if the gain knob is <=2.0.

If the gain knob is >2.0 the 20dB step appears in the transfer function (see elog page 5713). This step is shifted to higher frequencies if the gain is

increased. The PZT drive out was not saturated at any time. Yesterday, I checked the electronic circuit with a gain of 2.0. Thus,  I couldn't find the broken

gain amplifier (AD8336). The amplifier is ordered in will arrive on Monday.

ELOG V3.1.3-