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lbaops:lbafeb2009:vt11lholog [2015/12/18 16:38] (current)
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 +For 64 MHz (Hobart 1-bit) test.  We used the following setup:
 +BG3/Pulsar cable in (50 way from S2 recorder out, 2x20 way from correlator output ports 1 & 2 and 40 way into VSIC internal to the box)
 +DAS profile : MOP64.PRO ( and are probably OK as well).
 +Centre frequency 6558 MHz (Agilent 12.2 GHz, SMY 710 MHz).
 +**NOTE:** The Hobart 64 MHz filters are too broad - there is significant aliasing in at the top end of the band.  We used vsib_record to test the setup, which we ran manually in a FringeCheck directory on one of the xraids (vsib_record -t 10 s -w 64), because we couldn't get cdisko to do it.  Then fauto -n 256 <test_055_xxx> to look at the bandpass.  For IF#1 the bandpass looks like it is half a bandpass (centre at the bottom end) inverted.  However when I injected tones at the centre frequency, 16 MHz below and 16 MHz above I saw tones at the 1/2 1/4 and 3/4 points of the bandpass respectively (10 dBM on the vertex radiator gives a tone strong enough to easily see in 10 seconds without blasting the crap out of the system).
lbaops/lbafeb2009/vt11lholog.txt · Last modified: 2015/12/18 16:38 (external edit)