30 May 2018

T207_test

Finally a useful and fast tool to check the presence of T207 encoding in FSK bitstreams. The tool T207_test runs on Octave, a programming language for scientific computing, and was originally - and roughly - coded by me and then optimized and speeded-up by Christoph:

 Below an example where T207_test is successfully used on a 6 x 100Bd/120 VFT:  

The script builds a n x 14 test matrix and for each row computes the number of "1" bits in the first 12 columns; then check if the 13-14 bits value is the one expected according to the table below. Since the 2-bit 'checksum' can occur everywhere within the 14-bit frame, the stream is shifted up to 14 times building a new test matrix at each shift. The script counts the success checks for each test matrix and display the results. The better test matrix is also plotted along the frame start offset (ie after how many shifts).



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