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
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: 10673     Entry time: Wed Nov 5 22:25:42 2014     In reply to: 10669     Reply to this: 10675
Author: ericq 
Type: Update 
Category: LSC 
Subject: 3F RFPD RF spectra 

 

Now that I have followed the chain, the PD signal is indeed being amplified at the LSC rack. It goes into a ZFL-1000LN+ amplifier (~23dB gain at 165MHz and 15V supply), followed by a SHP-100 high pass filter, and then enters the RF IN of the demod board. 

I repeated the measurement in two spots.

First, I took a spectrum of the RF MON of the REFL165 demod board during DRMI lock; this was input-referred by adding 20dBm. 

Second, I inserted a ZFDC-10-5 coupler between the high pass and the RF input of the demod board. This was input-referred by adding 10dBm. 

REFL165_demod_DRMIspectrum.png

My calibration isn't perfect; the peaks above the high pass corner seem to be different by a consistent amount, but within a few dBm. 

Thus, it looks like the demod board is getting a little under -40dBm of 165MHz signal at its input. 

ELOG V3.1.3-