Hi, I have implemented Manchester (bi-phase-mark coding), Miller^2 and Xerxes line coding, transmission through a noisy channel, decoding, followed by a BER check, in an ~ 1.6 million cell LibreOffice spreadsheet.
I would really appreciate it if someone could point me in the direction of a good crash course on Octave scripting so that I can have a decent go at hacking mancyfsk.m etc ;) All three binary line codes tested were confirmed DC-free. I was surprised that over 100 kbit of random data (20x trials), all three codes had practically the same BER (about 0.023 for additive flat noise at 1.02 times the magnitude of the signal). I think that the big advantage of Miller^2 and Xerxes over Manchester are that they consume half the bandwidth of Manchester, meaning that we could either avoid the noisier upper half of the FM channel, or alternately, we could send bits twice as fast in the same bandwidth as a Manchester line code but a with 1/2 rate FEC. The channel in my spreadsheet has flat noise added to it (flat distribution of random numbers, not Gaussian) and I have not attempted to filter the channel or simulate FM modulation/demodulation. However, the same random data stream and channel noise is used for each line code under test, so I believe that it is still a fair test of the relative performance of the different line codes. I think that my SNR calculation is buggy because I have to select -0.2 dB SNR to get a BER of about 0.023. Anyone who is interested can access my spreadsheets on Google Drive: https://drive.google.com/open?id=0BzNXZIXmo93lS2FtZTFOdk5OekU "line code stats.ods" can be viewed online through Google Docs, however, "line codes.ods" is too big and you will need to download it if you want to open it (no, it does not use macros). 73 ZL2WRW Ross Whenmouth ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785471&iu=/4140 _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
