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Entry  Thu Jun 25 18:20:15 2015, ericq, Update, LSC, ALS reconstruction in progress 
    Reply  Fri Jun 26 03:24:18 2015, ericq, Update, LSC, ALS reconstruction in progress 
       Reply  Mon Jun 29 12:28:45 2015, ericq, Update, LSC, ALS reconstruction in progress 
          Reply  Tue Jun 30 05:47:38 2015, rana, Update, LSC, Use BALUNs 
Message ID: 11378     Entry time: Thu Jun 25 18:20:15 2015     Reply to this: 11379
Author: ericq 
Type: Update 
Category: LSC 
Subject: ALS reconstruction in progress 

I've been working on getting a working ALS up and running. Things are in a bit of a transient state right now; I'm off to softball and dinner, and will resume work tonight. There will be a more detailed ELOG then, but here are some quick notes:

  • c1als has been gutted, phase trackers are working successfully in c1lsc frontend. All channel names remain the same. 
  • BEATX is on the ADC channels where AS165 used to live, BEATY at POP55. 
  • Used a marconi to drive the aLIGO LSC demod board in the LSC rack, was able to lock digital phase tracker on two channels
  • Noise looks pretty cruddy. Lots of 60Hz harmonics on both channels, maybe from marconi drive? Pickup in the delay line?
  • BEATX whitening filter maybe has something fishy going on; excess noise at 2kHz
  • Unclear if BEATY whitening filter is actually doing anything. 
  • Whitening gain switching works fine for both, though. Haven't revisited the switching code, so its controlled in the old RFPD place for now.
  • Whitening triggering is not set up, will require some thought and model work that isn't neccesary yet. 
  • Agilent analyzer, marconi, and old delay lines are currently stashed behind the LSC rack; I will resume work with them tonight. 

The main thing left to do is to install the RF amplifiers at the PSL table and route the green beat signals over to the LSC rack. I fear that some investigation into the whitening filters will be neccesary to make the performance adequate, however. 

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