VEGAS Team Meeting

March 11, 2013


CALTECH, UC-B, & Columbia

Dan, Jayanth, Glenn


Jason, Ray, Marty, Anish, Paul, Mark


  • Update on timing issues
  • Review deliverables - consider consolidating modes

Meeting Notes:

  • Mode consolidation proposal from D. Wertheimer
    • compressing all 17 of VEGAS modes into 4 modes, which we think cover all the spectral resolutions and bandwidth's from table 2 of Anish's specification at:
    • restricting the number of VEGAS modes to four will make the software, hardware, testing and documentation easier, and make it easier on the astronomers, and i think this still does all the science outlined in anish's spec.the disadvantage is that some times the astronomers have more spectral channels than they need.
    • Proposed modes:
  1. Anish's Mode 1: 1024 channels, up to 3.2 Gsps
  2. Anish's Mode 2-5: 16K channels, up to 3.2 Gsps
  3. Anish's Mode 6-8: 128K channels, 250 MHz bandwidth (spectroscopy implemented on GPU)
  4. Anish's Mode 9-17: 32Kchannels in each of 8 sub-bands 25 MHz per sub-band (done on GPU)
  5. Mode 11 & 12 or one hi-res channels (30 Hz resolution)
    • OH maser science

Next Teleconference: March 18, 2012 .

Latest test results

Action Items from Last meeting
  1. Ray to make VEGAS simulator.
  2. A BOF for mode 13, or some other mode that uses GPUs.
    • (04-Feb) Not available yet
    • (11-Feb) 16 input version compiling now for subsequent test
    • (04-Mar) Should be ready to test in GB ~7-Mar
      • Need to refine what tests are done in Berkeley v. GB
        • Noise + tone tests in Berkeley
        • Replicate in GB (one Roach)
        • Build-out to eight Roach boards
        • Test on GBT
  3. A BOF with working switching signal logic.
    • (04-Feb) designed but still troubleshooting switching table loading issues
    • (11-Feb) Added to design for Mode #1
    • (11-Feb) Add sfp shift into manager
  4. A test and decision on what computers to buy.
    • (04-Feb) Not yet determined - Jayanth should go ahead with his tests to complete selection
    • (04-Feb) Needs HPC11.
  5. All Banks not starting at the same time.
    • (04-Feb) (above)
    • DONE (04-Mar) Resolved
  6. It will be good if we get the full spectral dynamic range corresponding to the 8 bit ADC in the next version of mode 1.
    • (04-Feb) Conduct initial tests at Berkeley, to see if there are any limiting issues for dynamic range and optimize
    • (04-Feb) what is/are the requirement(s) w.r.t full scale sin wave?
    • (04-Feb) is this a new requirement for the manager (yes)? is a parameter required to select between options? (parametrized shifting)
    • (04-Feb) what are requirements for shift parameter? depends on result of studying spectra...
    • (25-Feb)
  7. KFPA observation with mode 13.
    • (04-Feb) awaits mode 13
  8. Manager/VEGAS HPC code that will let two instances of the program be run simultaneously.
    • (04-Feb) not available, but not required for GC obs.
  9. Remember to do the RFI test of the rack.
    • (04-Feb) Not yet scheduled
  10. Roach to Valon serial port connection.
    • (04-Feb) Not yet implemented; not req'd for GC obs
  11. The I2C bus software tested with the manager and Galen's modules.
    • (04-Feb) Post GC Obs
  12. Add software version information into FITS file
    • (11-Feb) After GC obs

VEGAS observation preparation Status:

  1. "double start" issue -
    • Investigate with WireShark
    • look for duplicate data in FITS file (exists)
  2. Long Artificial Pulsar Test
    • Longer (3-hrs) by Anish
    • Ray to look at start up issues and then many ~5 min scans
  3. Request Ku-Band receiver installation
    • If long delay for installation, K-Band Pulsar test (reduced weather requirements)

Action Items:

Other items:

-- MartyBloss - 2013-02-25

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Topic revision: 2013-03-11, MartyBloss
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