TGBT18B_502_11 - FFTSHIFT and variance tests


  • Astronomical commissioning observations for all LBW modes.
    • All data will be taken on J1713+0437
    • Calibration and fold scans will be taken for all appropriate modes.
    • Search mode scans will be taken in all modes.
    • GUPPI will be used simultaneously as appropriate.
    • All science scans will be 900 seconds.


  • Session begins at 01:45. Joe starts switching to test VEGAS version.
  • Joe finished switching versions at 02:00
  • Scheduling block submitted at 02:01
  • First scan number is #14.
  • Pulsar detected in i0100x0512, though there seems to be every so slightly more smearing than in the GUPPI data, and the off-pulse noise in the phase vs frequency domain doesn't seem Gaussian. Will need to investigate this further.
  • i0100x1024 still not looking right. This is the mode where the apparent folding period is off.
  • i0100x2048 scan seems to have failed. This was the new BOF file build
  • Stopped SB and commented out i0100x0512 through i0100x2048. Resubmitted at 03:48
  • Bandpass levels are all zero for i0100x4096 with vscale = 5000. Trying again with vscale = 10000.
    • Still no power with scale at 50000 and 64000. I don't recall a previous problem with this. But going to move on...
  • i0200x1024 looks good. Seems like good agreement with GUPPI data
  • VEGAS failed to activate on i0200x2048 scan. Trying again. Same thing.
  • i0200x4096 and i0200x8192 scans seemed to run OK
  • Running low on time. Will need to reduce coherent scan lenghts to 5 minutes.
  • c0100x0064 looks good
  • c0100x0128 looks good
  • c0100x0256 looks good
  • c0100x0512 looks OK in fold mode, though power levels may be a bit low. Lots of packet loss in search mode.
  • c0200x0064 seems OK
  • c0200x0128 seems OK
  • c0200x0256 seems OK
  • c0200x0512 seems OK
  • c0200x1024 seems OK. Significant packet loss in search mode.
  • Session ended at 07:57. Joe switched back to release branch.
  • Checkouts done at 08:35.


  • Need to look at pulse width and off-pulse noise in i0100x0512
  • i0100x1024 still not looking right.
  • Need to look at i0100 modes and i0200x2048. Other modes seemed mostly OK. Will analyze in detail later on.
-- RyanLynch - 2019-02-28

This topic: CICADA > WebHome > GreenBankSpectrometer > CICADAGreenBankSpectrometerCommissioningLogs > CICADAGreenBankSpectrometer2019feb28
Topic revision: 2019-02-28, RyanLynch
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding NRAO Public Wiki? Send feedback