Cicada Topic

VEGAS Team Meeting

January 23, 2012

Attendees

  • CASPER Team:
    • Dan Werthheimer
    • Glenn Jones
    • Mark Wagner
    • Andrew Siemion

  • NRAO:
    • John Ford
    • Jason Ray
    • Randy McCullough
    • Mark Whitehead
    • Patrick Brandt
    • Galen Watts
    • Marty Bloss
    • Srikanth Bussa
    • Paul Demorest
    • Anish Roshi

Meeting Notes:

  • March Testing Status
    • Mode 1 working and tested at high clock rate
      • Made a number of changes in Mode #1 design and are working but not yet at high clock rate. V2 of CASPER 10Ge driver. Expect to have the high speed ability fixed by later in Feb. then a significant level of testing is needed. Tests mainly at UC-B. Final tests before March observations.
    • IF/LO hardware
      • Still haven't identified cause of gain slope across band. Looking at freq equalizers combined with attenuators that will result in gain slope of ~1db from 100-1400 MHz.
      • Will need to make a revised PCB FR4 board.
      • Adding more attenuation in the noise source chain
      • Added I2C control capability.
      • Need 8 IF modules (16 channels) minimum for March testing (possible)
      • Should be stable in environmentally stable location
      • I2C drivers are working, parameters are in place, ready for testing
    • Config Tool/Balancing
      • Anish is working with Melinda to finish MR
        • Ability to do Galactic Center obs. will be in place for March Test (Config tool)
        • Balance is a more general but needed for March Obs.
    • ADC testing
      • Both ADCs tested for full bandwith. Spurs are about the same. Srikanth has circulated band shape here. Input power is constant across band so cable losses are negligible. There is a balun on input which may be the cause of what roll-off we have seen. Cross-coupling measurements are complete - results to be circulated. Currently spurs are similar between units (unadjusted).
      • GB to review test results and make recommendation for purchase. (due Jan 27)
    • Gathering of Roach and ADC hardware
      • Five roaches available for the test, eight needed - UC-B can make up the balance
      • Eight plus eight ADCs available (Nationals)
      • Spars from existing gear if needed
      • need a data acquisition PC w/ 10Ge NIC, 10Ge switch, cables
    • Approval of the following MR/PRs by the CCC (This section was updated after the meeting by NRAO)
      • VEGAS Manager
        • Ready for integration tests using system simulator generated data (test tone data through SDFITS). Measure highest sustained data speed capable. Populate switching table for use by FPGA.
      • IF Manager
        • Ready for integration tests in GBT system to support IF/LO I2C protocols above and populate the VEGAS FITS file with bandwidth and filter information
      • GBT status
        • (Not required for March test) Requirements received, SDD reviewing and will draft MR based on Reqs. Developer resource not yet identified
      • switching signal selector
        • Ready for integration tests using system generated data.
      • Antenna position reading at faster rate (Joe Brandt; needed for approved KFPA project)
        • Requirements are needed from Joe to write the MR (if needed). Mark and Joe to meet and discuss
      • Balance
        • MR drafting underway. Melinda and Anish refining requirements. NRAO scientific review of project-delivered information will gate the completion of this MR
      • Config tool
        • MR drafting underway. Melinda and Anish refining requirements. NRAO scientific review of project-delivered information will gate the completion of this MR
      • Connecting VEGAS to the GBT data storage system.
        • (Removed as a requirement for March)
      • Testing VEGAS Manager to write data at the required speed to the data storage system.
        • (Removed as a requirement for March) Under test for writing data, but not to data storage until the array is commissioned.
      • Integrated testing of VEGAS manager with other GBT software and checking the data with GBTIDL.
        • Remaining work requires testing of files generated in simulator for GBTIDL staff review
      • Testing the VEGAS Manager along with GBTIDL to see whether the state integration is done correctly.
        • Complete – requires testing of files generated in simulator for GBTIDL staff review
      • Testing VEGAS configuration for mode 1 (and 13) using config tool.
        • Goal for March, config tool availability contingent on MR approvals and completion of items above.
  • Roach "disconnect" issues
    • Permanent address have been assigned to the Roaches and that should clear the problem.
  • Sub-band specification in modes 13-17
    • Format of the user input: Eight sub-band center frequencies plus the mode (e.g. mode 13 + 8 frequencies).

-- MartyBloss - 2012-01-23
Topic revision: r3 - 2012-01-24, JohnFord
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