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This program is used to take spectra and total power measurements.
It records spectral and total-power data to external datalogging
files.
The program takes the following options:
--rx-subdev-spec which USRP Rx side? A or B
--decim USRP decimation rate: 8, 16, 32, and 64 are good
(8Mhz, 4Mhz, 2Mhz, and 1Mhz bandwidth)
--freq USRP daughtercard frequency
--observing Actual observing frequency (default is to use the
setting for --freq)
--avg Averaging setting for spectral display--higher numbers
equal more averaging. 25 to 40 is typical.
--integ Total power integration time: seconds
--gain USRP daughtercard gain control
--reflevel Reference level on pulse profile display
--longitude Observer longitude: West is negative
--latitude Observer latitude: South is negative
--fft_size Size of FFT for post-detector spectrum: default is 1024
--prefix Filename prefix to use for data logging files
Default is ./
--divbase The base of the Y/Div menu in pulsar display
--division The initial Y/Div in pulsar display
--ylabel Y axis label
--cfunc The function name prefix for the spectral and
calibrator functions
--waterfall Use waterfall, rather than regular spectral display
NOT TESTED IN THIS APPLICATION
--stripsize Size of the total-power stripchart, in samples
There are two windows--a spectral window, and the total-power window.
Moving the cursor around in the spectral window shows you the
corresponding frequency and doppler shift. Left clicking in this
window sets an interference marker, which sets a "zero" in the
interference filter. Use the "clear interference" button to clear this.
The total power window is updated at a fixed 2Hz rate, and grows from
the left of the display.
If latitude and longitude are set correctly, and system time is correct,
then the current LMST is displayed, updated once per second.
Averaging parameters, gain, and frequency can all be set from the GUI using
the appropriate controls. You can also enter the current declination, which
will appear in the datalogging files. This is useful both for mapping,
and housekeeping purposes, particularly when you haven't looked at a datafile
for quite some time.
There are two datalog files produced by this program:
YYYYMMDDHH.tpdat Total power data
The date/time portion of the filename is referred to local time,
rather than UTC or sidereal.
First field is sidereal time when sample was taken
Second field is total power datum
Third field is declination in decimal degrees
Samples are written once per second
YYYYMMDDHH.sdat Spectral data
The date/time portion of the filename is referred to local time,
rather than UTC or sidereal.
First field is sidereal time when spectrum was taken
Second field is declination in decimal degrees
Third field is complex spectral data--in the same order that FFTW3 library
places bins: DC to bandwidth/2, followed by -bandwidth/2 to DC.
Spectral snapshots are written once every 5 seconds
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