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Entry  Wed Jan 19 04:25:54 2011, Kevin, Update, Electronics, POX Transfer Functions 
    Reply  Wed Jan 19 10:45:00 2011, Koji, Update, Electronics, POX Transfer Functions 
       Reply  Wed Jan 19 17:00:23 2011, Kevin, Update, Electronics, POX Transfer Functions 
          Reply  Thu Jan 20 01:50:30 2011, Kevin, Update, Electronics, POX Transfer Functions 
Message ID: 4167     Entry time: Wed Jan 19 04:25:54 2011     Reply to this: 4169
Author: Kevin 
Type: Update 
Category: Electronics 
Subject: POX Transfer Functions 

I redid the optical POX transfer functions and updated the wiki at http://lhocds.ligo-wa.caltech.edu:8000/40m/Electronics/POX.

I measured each transfer function several times to calculate uncertainties for each measured point. There is one large transfer function from 1 MHz to 500 MHz showing a resonance peak at 11 MHz and notches at 22 MHz and 55 MHz. I also made more detailed measurements around each of these resonance peaks. These measurements were fit to a resonance curve to determine the resonant frequency, transimpedance at resonance, and Q for each peak. These measurements agree with the shot noise measurement for the transimpedance at 11 MHz taken earlier considering that this measurement was made at 11 MHz instead of at the resonant frequency of 11.14 MHz.

I measured these transfer functions with the Agilent 4395a using the netgpib.py script last week. I realized that when using this script to save multiple copies of the same measurement after setting up the instrument, the first and second measurements are saved but all measurements saved after are identical to the second measurement until the instrument is physically reset. This happens because the analyzer switches the trigger from continuous to hold after making a measurement using this script. Kiwamu said that the script can be modified to return the trigger to continuous after saving the data so that multiple measurements can be saved without being at the analyzer physically. I did not want to waste more time figuring out how to modify the script to do this so I used one of the netbooks and sat at the analyzer manually returning the trigger to continuous after each measurement.

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