VEGAS Pulsar Project Meeting: 2015 May 18th 2:00 - 3:00pm ET

Room / Connection Details

  • GB-137 / Soc 280
  • 192.33.117.12##7144
  • 434-817-6443

Housekeeping Details

  • Main wiki page
  • gbsapp Mailing List
  • Location and regular date and time of meeting - agreed weekly on Mondays; GB-137 / Soc-280; 2-3pm ET
  • ETK codes:
    • Electronics: 432510.GB3015
    • Software: 893252.GB3015
    • Science: 432540.GB3015

Resource Allocations

GUPITA, ARINDAM 1.00
FORD, JOHN 0.10
MCCULLOUGH, RANDY 0.40
RAY, JASON 0.55
BLOSS, MARTY 0.05
CREAGER, RAY 0.8
RICHMOND DECKER, JUSTIN 0.0
LYNCH, RYAN 0.25
DEMOREST, PAUL 0.25
PRESTAGE, RICHARD 0.1

Present

  • Jason, Randy, Richard, Arindam, Paul, Marty, John, Ryan

Agenda

General Updates

  • New BOF files * Arindam, Jason, and Randy uncovered error in i0800x2048 bof causing some incorrect packets; now fixed * Continuing to build under Xilinx v14.7 * Ryan is testing new builds with AP; i800x1024 build looks good
  • Manager
    • Manager is now working consistently with incoherent modes and writing fits files * Ryan did some basic tests using psrchive and fits files, and they appear to be in correct format
    • Coherent modes are still not working properly
      • Can run scans when status memory is set to be identical to DIBAS, but after switching modes scans fail
      • Need to check status memory values more closely to be sure all parameters are being set correctly when switching modes
      • Manager can write and read from ROACH, problems seems to be in guppi_daq_server and the values it is getting from the ROACH
      • Justin, Paul, Ryan, Randy, Jason, and Ray will meet Wednesday at 11:00 AM to go over things more closely
    • Manager also needs to increment scan number to avoid duplicating file names
  • Valon tests
    • Over the weekend, the original valon on srbs got into a bad state
      • Could not communicate with it, Jason had to do a power cycle but it came back in proper state afterward
    • Paul's tests of drifts and instability using 10 MHz reference signal showed only minor drift rates of 10s of ns over many hours, not enough to explain periodicities seen with AP
      • Jason and Ryan will put the original valon back in a "bad" state and try to recreate the TOA periodicities
      • May also try using different signals for ADC clock reference and input signal (rather than 10 MHz for both)
  • New ROACH board is ready to be hooked up and should be online later this week

Discussion

  • VPM file name convention
    • GUPPI currently writes file names with the format guppi___<SCAN#>_<SUBSCAN#>.fits, e.g. guppi_57160_APsr_0001_0001.fits
    • This is not optimal because it is possible to duplicate file names, but keeping the source name and MJD in the file name is convenient for pulsar observers
    • When VPM and spectral line modes are rationalized we will probably want to change the VPM file naming scheme
      • One suggestions is to totally duplicate spectral line modes, which is a time stamp with directory structure providing information on backend, etc.
      • Ryan would prefer to keep MJD and source name but perhaps replace scan numbers with something time based, e.g. seconds after 00:00 UTC or HHMMSS
  • Wideband artificial pulsar
    • We decided it would be good to have a wideband pulsar as soon as possible, rather than waiting for a student to finish the project next year
    • Schematic is done and circuit board design has been started, but may want to redo it
    • Randy estimates that a basic model without any dispersive capability could be finished over the summer, possibly for around $3k
    • We decided to pursue this using existing funds and charging it to VPM project code
    • Student could then add functionality, such as dispersive transmission line, as a senior project

Date / Time of Next Meeting

  • June 1

-- RyanLynch - 2015-05-04
Topic revision: r1 - 2015-05-18, RyanLynch
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