VEGAS Team Meeting

February 04, 2013

Attendees

CALTECH, UC-B, & Columbia

Dan, Jayanth, Mark, Andrew, Glenn

NRAO:

Jason, Ray, Marty, Anish, Randy, Paul

Meeting Notes:

Next Teleconference: February 11, 2012 .

Postpone observations until the receiver is replaced.

Latest test results

• additional FITS file fields should be added to capture counts and other useful troubleshooting items (D)

UTCdelta issue

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UTCdelat issue is different now. In almost all files the first integration is large by about 5 micro sec. There are glitches in UTCdelta at about 5 nano sec (about one FPGA clock) (see utcglitch_jan27.png). In one of the files (/lustre/gbtdata/TGBT12B_504_06/VEGAS/2013_01_27_23:39:58) there is jump in utcdelta and the magnitude of the jump is different for different Banks (see utcd1_jan27.png).

Fixed.

Varying delays in bands

We see jumping of different times in varying bands of UTCdelta after an observation has run for a period (R)

Anish to re-run tests to attempt to replicate errors

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Start time Alignment

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Start time of data are aligned in almost all files. In two files, the start time of bank A is off by 28 micro sec.(D)

Re-test by doing several short iterations with existing function generator short gaps and see if they can be stitched together.

Step in time series

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Noticed a step (~few percent) in the time series obtained from collapsing channels 100 to 900 (see timeser_jan27.png). May not be an issue for pulsar obs.

Re-test

Action Items from 28-Feb

1. A BOF for mode 13, or some other mode that uses GPUs.
   • Not available yet
2. A BOF with working switching signal logic.
   • designed but still troubleshooting switching table loading issues
3. A test and decision on what computers to buy.
   • Not yet determined - Jayanth should go ahead with his tests to complete selection
4. All Banks not starting at the same time.
   • (above)
5. 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.
   • Conduct initial tests at Berkeley, to see if there are any limiting issues for dynamic range and optimize
6. KFPA observation with mode 13.
   • awaits mode 13
7. Manager/VEGAS HPC code that will let two instances of the program be run simultaneously.
   • not available, but not required for GC obs.
8. Remember to do the RFI test of the rack.
   • Not yet scheduled
9. Roach to Valon serial port connection.
   • Not yet implemented
10. The I2C bus software tested with the manager and Galen's modules.
    • Post GC Obs
11. The ROACH uboots reflased (1-6).
    • May be accomplished any time with access to system (Feb 5)
12. The tcpborphserver init script needs configured.

VEGAS observation preparation Status:

1. Sort out the timing issue in utcdelta
   • postpone obs until this is fixed
2. Fix board crashes (maybe not a barrier to obs.)
3. what tests should we do before we have enough confidence to start observing?
   • Test Pulsar
     • more tests after new fits fields are added

Action Items:

Other items:

-- MartyBloss - 2013-02-04