Comparison of beam-formed signal, before and after filtering
Day 245, 2001
( logbook log of Nov. 4 2001 )
Data from one 2-hour data file from day 245 (September 2), 2001. The upper plot shows the signal, digitized at 1000 Hz, from the VLA. The four channels have been averaged, giving some horizontal directionality to the array. The lower plot shows the signal after filtering through a pass band centered at 260 Hz, about 2 Hz wide. There are Webb signals at 245.1912 days (SS1) and 245.2325 days (SS3),showing up clearly in the filtered signal but not at all apparent in the unfiltered signal. The filtering also does a fairly good job of rejecting the various signal spikes seen on the upper plot.