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Дата изменения: Sun Oct 10 18:37:24 2010
Дата индексирования: Fri Feb 11 08:45:42 2011
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A2488: dps with 800 Mhz rcvr
may08
Intro:
A2488 is using double position switching on sources
using the 800 Mhz receiver. The mock spectrometer is used to record the
data. The setup is:
5Mhz, 8Mhz, and 172 Mhz bands taken. Each with 8192 channels.
1 second dumps
240 seconds on and off source and calibrator.
Compare polA with polB (10aug09)
The observers reported that the rms for polB is
about 70% larger than the rms for polB. This is measured across the dps
spectra result.
The dps processing is:
top: mean spectra value vs dps scan number. black is pola, red
is polB.
Two separate sources/calibrators were looked at.
there is an oscillation in the dps mean value.
bottom: Rms value across each spectra vs dps scan number
Rfi has been removed before computing the rms
polB rms is greater than polA rms except for the 2nd source.
Page 2: dps mean spectral value vs az,za
Top: mean dps spectra value vs azimuth:
there is a clear 180 deg period implying polarized power
coming in from somewhere.
bottom: Mean dps spectral value vs za.
SUMMARY:
The rms for polB is larger than the rms for polA
There is polarized power in the average dps spectra. The
amplitude is about 10%. the source is around 1631+11. This is in the
top part of the north polar spur which has polarized power (although
you might expect the calibration to remove this).