TGBT15A_915_92 - Test Stokes U and V with new VEGAS bof file


  • Test behavior of Stokes U and V data with a new BOF file that uses registers in place of delay elements.


Session begins at 10:00
  • Switched VEGAS to pulsar branch
  • Will use 00-CoherentModeArtifactTesting in c1500x0512 mode (this is the mode the BOF file was built for). Will set-up at S-Band to try to avoid FFT overflow issues.
  • Taking one scan with current BOF file (c1500x0512_x14_7_2016_Feb_24_1437.bof) for comparison
    • SB submitted at 10:06
    • Scan is #1
    • SB ended at 10:08
    • Accidentally had vegas.fold_dumptime set to 1.0 seconds, so there are lots of sub-integrations. Data should be fine but going to take another scan anyway
  • Taking second scan with current BOF file, 10-s dump times.
    • SB submitted at 10:10
    • Scan is #2
    • SB ended at 10:11
    • Data don't look great. It's almost like there are drop-outs in the phase domain. Dropped packets? Something wrong in the PFB? Definitely seeing phase wraps in U/V, though.
  • Switching to test BOF file (c1500x0512_x14_7_rtd_2017_Mar_21_1121.bof)
    • SB submitted at 10:22
    • Scan is #3
    • First attempt failed to start HPC subprocess and aborted. Maybe a systemstop/start is needed.
    • Resubmitted at 10:26
    • Scan is #4
    • SB ended at 10:28
    • No obvious changes in U/V data
  • Going to take a scan using test BOF file but at L-Band. Will try changing fftshift to all f's and set vegas.scale to 110
    • SB submitted at 10:37
    • Scan is #5
    • SB ended at 10:39
    • We are getting dropped packets. Possible source of the features in the phase-domain?
  • Taking one more scan to look at dropped packets
    • SB submitted at 10:45
    • Scan is #6
    • SB ended at
    • Seem to have consistent 30% dropped packet rate
  • Switched to release mode at 10:48
  • Taking verification scan
    • Using CheckMode1 scheduling block
    • SB submitted at 10:52
    • Scan is #7
    • SB finished at 10:52
    • Data look good
Session ended at 10:54


Phase wrap in Stokes U and V data still seems to be present with new BOF file, but dropped packets could complicate interpretation.

-- RyanLynch - 2017-03-22
Topic revision: r2 - 2017-03-22, RyanLynch
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