Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.naic.edu/~phil/usrproj/a2488/a2488.html
Äàòà èçìåíåíèÿ: Sun Oct 10 18:37:24 2010
Äàòà èíäåêñèðîâàíèÿ: Fri Feb 11 08:45:42 2011
Êîäèðîâêà:
Ïîèñêîâûå ñëîâà: ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï

a2488 dps the 800Mhz rcvr.

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:

Compute onoffSrc=OnSrc-offSrc
compute onoffBpc = onBpc - offBpc (bpc = bandpass calibrator)
dpsSpectra= onoffSrc/onoffBpc

The processing leaves the dps spectra in units of the bandpass calibrator source strength.

Plots were made of the average spectral density and rms value for 35 dps spectra (.ps) (.pdf):

Page 1 vs dps scan number

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).

processing: usrproj/a2488/10aug09.pro

home_~phil