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Entry  Wed Nov 5 01:58:54 2014, ericq, Update, LSC, 3F RFPD RF spectra Nov52014_3fPD_DRMIspectra.zipREFL165_DRMIspectrum.pngREFL33_DRMIspectrum.png
    Reply  Wed Nov 5 11:09:44 2014, Koji, Update, LSC, 3F RFPD RF spectra 
       Reply  Wed Nov 5 22:25:42 2014, ericq, Update, LSC, 3F RFPD RF spectra REFL165_demod_DRMIspectrum.png
          Reply  Thu Nov 6 01:58:55 2014, Koji, Update, LSC, 3F RFPD RF spectra 
             Reply  Thu Nov 6 11:49:58 2014, ericq, Update, LSC, 3F RFPD RF spectra 
                Reply  Thu Nov 6 14:41:49 2014, Koij, Update, LSC, 3F RFPD RF spectra 
                   Reply  Fri Nov 7 02:21:12 2014, ericq, Update, LSC, 3F RFPD RF spectra 
                      Reply  Fri Nov 7 14:41:18 2014, ericq, Update, LSC, 3F RFPD RF spectra 165_ampSaturation.png165_HPatPD.png
                         Reply  Fri Nov 7 16:15:53 2014, Jenne, Update, LSC, 3F RFPD RF spectra 
                            Reply  Sat Nov 8 11:35:05 2014, rana, Update, LSC, 3F RFPD RF spectra 
                            Reply  Mon Nov 10 18:11:57 2014, ericq, Update, LSC, 3F RFPD RF spectra 165signals.pdf
Message ID: 10668     Entry time: Wed Nov 5 01:58:54 2014     Reply to this: 10669
Author: ericq 
Type: Update 
Category: LSC 
Subject: 3F RFPD RF spectra 

Given the checkout of the aLIGO BBPDs happening (aLOG link), wherein the PDs were acting funny, and Koji has made some measurements determining that intermodulation/nonlinearity of circuitry can corrupt 3F signals, I've made a similar measurement of the RF spectra of REFL165 when we're locked on DRMI using 1F signals. Maybe this could give us insight to our bad luck using REFL165...

In essence, I plugged the RF output of the PD into an AG4395, through a 10dB attenuator and downloaded the spectrum. I also did REFL33 as a possible comparison and because why not. The attached plots have the 10dB accounted for; the text files do not. 

REFL165 (Exposed PCB BBPD):

REFL165_DRMIspectrum.png

(What is all that crap between 8 and 9 fmod?)

REFL33 (Gold Box resonant RFPD):

REFL33_DRMIspectrum.png

Attachment 1: Nov52014_3fPD_DRMIspectra.zip  350 kB
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