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Entry  Wed Apr 3 17:40:18 2013, Jamie, Configuration, Electronics, putting together a 110 MHz LSC demod board 
    Reply  Wed Apr 3 18:41:22 2013, Jamie, Configuration, Electronics, putting together a 110 MHz LSC demod board 
    Reply  Wed Apr 3 22:26:51 2013, rana, Configuration, Electronics, putting together a 110 MHz LSC demod board 
       Reply  Thu Apr 4 14:37:15 2013, Jamie, Configuration, Electronics, putting together a 110 MHz LSC demod board 
          Reply  Mon Aug 26 18:55:18 2013, Jenne, Configuration, Electronics, putting together a 110 MHz LSC demod board for AS AS110_demod_board_modifications.pdf
             Reply  Mon Aug 26 20:13:17 2013, rana, Configuration, Electronics, putting together a 110 MHz LSC demod board for AS 
                Reply  Tue Aug 27 15:31:48 2013, Jenne, Configuration, Electronics, putting together a 110 MHz LSC demod board for AS 
                   Reply  Tue Sep 3 21:10:36 2013, Jenne, Configuration, Electronics, putting together a 110 MHz LSC demod board for AS 
             Reply  Tue Aug 27 17:32:52 2013, Jenne, Configuration, Electronics, putting together a 110 MHz LSC demod board for AS 
                Reply  Tue Aug 27 18:21:35 2013, Jenne, Configuration, Electronics, 110 MHz LO options 
                   Reply  Tue Aug 27 18:58:52 2013, Koji, Configuration, Electronics, 110 MHz LO options 
                   Reply  Mon Sep 2 16:46:32 2013, Jenne, Update, Electronics, RF distribution box is on the bench 
                      Reply  Mon Sep 2 18:06:21 2013, Jenne, Update, Electronics, RF distribution box: 110 MHz LO options RF_distribution_box_proposed_modifications.pdf0902131751.jpg0902131751a.jpg
                         Reply  Tue Sep 3 21:08:13 2013, Jenne, Update, Electronics, RF distribution box: 110 MHz LO options 
                            Reply  Wed Sep 4 16:06:40 2013, Jenne, Update, Electronics, RF distribution box: Reinstalled 
                               Reply  Wed Sep 4 21:44:54 2013, Not Jenne, Update, Electronics, RF distribution box: Reinstalled 
Message ID: 9071     Entry time: Tue Aug 27 17:32:52 2013     In reply to: 9062     Reply to this: 9072
Author: Jenne 
Type: Configuration 
Category: Electronics 
Subject: putting together a 110 MHz LSC demod board for AS 

I measured the phase split between the I and Q signals of my AS110 board.  To do so, I plugged the board into an empty slot next to the PD DC readout / whitening board in the LSC rack.  I borrowed the POP110 local oscillator, and used a Marconi to generate a "PD input".  (I'm roughly following what Suresh did in elog 4736).  Our 11MHz is currently 11.066134MHz, so I had the Marconi going at 110.662340 MHz (1kHz from 10*11MHz), and I had the Marconi source at -13dBm.  

I took a transfer function using the SR785 between the I and Q outs of the AS110 demod board, and got a magnitude misbalance of 0.809 dB, and a phase split of 110.5 degrees.  This isn't so close to 90 degrees, but this may be a problem with the splitter that we're using, as Suresh detailed in elog 4755.  In that elog, he measured a phase split of POP110 of 105 degrees, unless the power going into the splitter was pretty high.  As with POP110, since I expect that we'll usually only look at one channel (I, for instance), this isn't such a big deal for AS110. 

I have left, for now, the board in the empty slot.  It looks like (I'm going to go check) there are 3 open channels on the whitening board that has the PD DC signals.  So, the only thing left to figure out is how we want to get some local oscillator action for this new board.

EDIT: Yes, those channels are available.  Right now (as a remnant from testing the whitening filters waaaay back in the day) they are called C1:LSC-PDXXX I, Q, DC.  I'll use 2 of those for the AS110 I and Q. 

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