Data Displays

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There are two types of SonATA data displays. The Waterfall Display the and the Baseline Display. Currently they get their data from the Disk. Both displays are written in the Java programming language.




The Waterfall Display shows the power for each bin in a subchannel.

Sonata waterfall.jpg


waterfallDisplay -file < filename > -res < 1 | 2 > -xpos < x position > -ypos < y position > -slow -repeat -suboff < subband offset > -batch -outfile < outFilename >

Reads a file containing complex amplitudes and display it in a GUI as a waterfall. Frequency is on the x-axis, time on the y-axis, power as brightness). This program can also be run without the GUI, sending the waterfall image to a jpeg file instead.


-file: input filename.

The file suffix is usually .compamp or .archive-compamp.
The .compamp file contains a single subband.
The .archive-compamp file contains 16 subbands, and the
signal of interest usually falls in the center, subband 8.

-res: data display resolution in Hz (1 or 2)

-xpos: window x position

-ypos: window y position

-slow: play slowly

-repeat: repeatedly read data file (i.e., endless replay)

-sonata: data file is in sonata packet format

-suboff: subband offset to display (0-15) for .archive-compamp files

-batch: no GUI, send waterfall image to jpeg file

-outfile: output filename for batch mode (default: 'waterfall.jpeg')


waterfallDisplay -file


The DX generates “confirmation data” which is baselined 4-bit real, 4-bit imaginary complex amplitude values at 1 kHz resolution, with 384 values per subband per half-frame. A half frame is generated approximately every 3/4 second.

During data collection, the DX can be asked to send a single subband's worth of data, for any arbitrary subband, in realtime. The waterfall program FFTs two sequential half-frames of complex amplitudes to create a single row of “1 Hz” frequency data. Each of the 768 bins in the row actually represents .694444 Hz, and the entire subband is 533.3333 Hz wide.

The waterfall display also has a “2 Hz” mode, where a single half-frame (i.e., no overlapping data) is used to create a 384 point row. A further option for “4 Hz” mode produces a 192 point row.

At the end of signal detection, the DX can be asked to send archive data for candidate signals. This archive data consists of 16-subbands worth of “confirmation data” surrounding each candidate. The waterfall program has an option to select any single subband out of the 16 for display.



The baseline display shows the average power in each subchannel over channel bandwith. The baseline is averaged over time and is reported on the display.

Sonata baseline.jpg


baselineDisplay -file < filename > -xpos < x position > -ypos < y position > -width < width > -height < height > -slow -timeavg

Reads a file containing DX baseline data and display it as a frequency vs. power XY plot.


-file: NSS baselines filename. File suffix is usually .baseline.

-xpos: window x position

-ypos: window y position

-width: window width (default: 660)

-height: window height (default: 400)

-slow: display data slowly

-timeavg: display data as a time average


baselineDisplay -file 2007-02-13_00-53-12_UTC.act440.iftest.unit7.pdm42.L.baseline

See also

External links

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