
Pathfinder DVL Guide
April
2018
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Page 57
11. If you still don’t see any plots after 30 seconds please exit the NGSPFFT software and reopen
TRDI Toolz and assure you are talking at CB811 (115200 baud).
Check the Adjustments
At the bottom of the NGSPFFT window assure the “FFT N”=”512”, “Window”=”ON”, “Filter”=”Off”. Also
set NB & HG.
Zoom
By clicking on the “beam” of interest, you can zoom in to see only that beam. Click again to zoom out.
Mouse-Over:
By placing the cursor over a frequency of interest, a mouse-over window will appear with more infor-
mation about that frequency and amplitude.
Examples of Clean FFT Plots, No Interference
The following is a screen shot of a typical “clean”, 512 sample, FFT of a 614,400 kHz Pathfinder. The
bandwidth of the plot is approximately 23 to 24% and is typical of the Pathfinder FFT in broadband re-
ceiver mode. NB mode is about 25%.
The following is the same “clean”, 512 sample FFT, with the “Filter”=”ON” radio button selected. It is
simply a moving average of the last 30 FFTS.
The color changes from red to blue once the FFT has acquired an average of the 30 previous.