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TGBT14A_912_99 - Compare Mode 10 (hw), Mode 10 (sw) Mode 23
Compare spectra taken in Mode 10 (hw), Mode 10 (sw) Mode 23
9:30am load software, check Astrid scripts
Adam uses X-band receiver, so configure for that also (may not be at focus), even though we are using the noise source
noise_test_mode10_xband_nocal - lbw_gain set to 4096 (this is L8 BOF, not L1 BOF)
adc and sb1snap powers approx -18dBm
Run scans 1-11
bandpass shape looks bell-shaped, L & R polarizations identical. All 11 scans look identical
noise_test_mode23_xband_nocal - lbw_gain still set to 4096 (this is L8 BOF, not L1 BOF)
Run scans 12 - had left nwin = 1, switch to nwin = 8 (and 8 restfreqs)
Scan 13 - now 8 windows, wasn't setting all 8 lbw_gains, fix this. Get the syntax wrong and crash Grail, try a different syntax.
Still can't get it right, just do it manually
Scan 14 - now working correctly. All look identical, but below Mode 10 scan
Run Scans 15-24
12:10pm. Joe switches to "no software fix" version, and latest BOF (l8_ver160_1500_2015_Dec_15)
Scan 25 - looks different again!
Scan 26-35 - 10 more of the hardware version of mode 10. lbw_gain still 4096
Scan 25 and 32 are off
top white line (at center) = hardware mode 10, red (middle) = software mode 10, white (bottom) = mode 23
noise_test_mode23_xband_nocal (using new BOF)
Scan 36 - had lbw_gain of 1024 (default value)
Scan 37 - lbw_gain = 4096, sb1snap = -9dBm
revert to mode 10, lbw_gain = 4096 - looks correct
Mode 23, lbw_gain = 1024 give -20.5dBm
Scan 38,39 - Mode 23, new BOF, no fix necessary, lbw_gain = 1024. Spectra power level is way low. 1.1 10**9 c.f. 2.5 10**10
Switch to 2**10.5 (1448) now looks ok. Histograms are thinner than mode 10, because mode 23 histogram only shows one component of power.
Scan 40 - goes from 1.1 10**9 to 2.4 10**9
Switch back to lbw_gain of 4096. Seems to produce spectrum power same as mode 10, although sb1snap is ~ -9dBm
Scan 41 - 50 mode 23 (new BOF)
Conclusion: old Mode 10 (sw, old bof) and new Mode 10 (hw, new bof) match, but new bof is bistable
old mode 23 and new mod 23 agree, but are different from mode 10
Joe notes they are using different coefficients.
1:25pm - finito
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Topic revision: r2 - 2015-05-22,
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