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TGBT14A_912_91 - Continuing tests
Continue tests from yesterday
8:00am - switch VEGAS versions, etc
Configure for all eight banks of VEGAS
bank_gain_mode1_xband (all 8 banks)
scans 1-3: track - results look "normally bad"
Galen terminates all of the "0" inputs (A0,B0...H0) at inputs to VEGAS IF modules
No other rebalancing or anything.
scans 4-6: track.
set up with ADC Bank A = A0,B0, B=A1,B1, C=C0,D0,D=C1,D1... same for E through H.
Doors now closed
scans 7-9. Track
scan 10-12. Track - looks similar to 7-9
Terminate all "1" inputs (A1,B1...H1) at inputs to VEGAS IF modules
Scans 13-15. Track
Put one signal into each of eight IF modules, with other input terminated.
ADC banks A,C,E,H, A = A0,A1, C=C0,C1, etc...
As above, but flip optical receiver paths in cabling.
A swapped with E, C swapped with G.
Tsys switches as expected
CM1 - switch OR1 to OR2, same in CM2,3,4. In IF Rack, switch S9. need to set filter and attenuator for this OR path, but cannot exceed 3V
Need to set CM1 and CM3 attenuators to remove attenuation
This switches a single optical receiver path, but uses the same converter modules (as confirmed by Galen!)
Scans 22-24 - all lines up.
Switch back to 19-21 configuration. Did NOT need to change converter rack attenuation, implying OR attenuator was previously wrong.
Scan 25-27 - all line up
Conclusion - Tsys offsets above seem to have been caused by an over-driven optical receiver, which has been there since the very first balance. So, we believe that has gone away.
ADCs A,C,E,G have their correct configurations. (A0 is connected as normal. A1 goes to B0, then back to A1 ADC).
cabling file checks: create a bunch of "_fixed" scripts, which configure for 4 banks. Make sure everything works.
scan 27 - bank_gain_mode1_xband_fixed, banks hard coded. Looks fine. Take out hard coding, and everything works as expected.
28: mode 4. Tsys = 28.81,28.91,26.36,26.37; bandpass shapes different. Dave's routines won't work on these - not sure why not.
29: mode 7. Fails to do internal requantization balancing - perhaps due to inconsistent BOF file / Manager?
Since we don't have all new BOFs, need to switch back to "production" manager anyway.
30: mode 4 (old BOF). - ok
31: mode 1 - ok.
32: mode 7 - configures and balances ok, but aborts with an "invalid data" error. Cycle VEGAS Off and On. Seems to fix the problem.
33: mode 7 - ok
34: mode 19 - ok. Consistent Tsys values to 0.05K /0.01K within same pols, 2.0K between Pols (7%)
We believe we have found the "cross-talk" problem.
Astronomical tests to do
Make sure the cabling file modification allows us to configure correctly.
Repeat the "good" configuration tests on every different BOF combination: Mode 1,2,4,10, the Balser mode (can't remember it now, 20 or 21)
Repeat the "good" configuration on a strong flux calibrator in the above four modes.
Repeat the "good" configuration with Dana's RRL setup.
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Topic revision: r6 - 2015-04-20,
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