Graham,
On 24-10-12 17:29, Graham Bryce wrote: > Secondly - Having only looked briefly at the Golay code you're advocating, > it does look like a good option - there is a guaranteed Hamming distance of > 3 for every transmitted data bit (i.e. one bit change in the original > code-word results in 3 bits changing in the transmitted codeword), which is > really quite high. I agree that a better option for a "strangled" Golay code > to reduce it from being a 1/2-rate code (i.e. 12 extra bits added to the > original 12 data bits) to being a 2/3-rate code (i.e. 6 extra bits per 12 > originals) would be to reduce the Hamming distance to 2, which I'm hoping > you can achieve by careful removal of 6 of the "added" ECC bits. This would > then, as you say, lead to all the payload bits having some ECC, rather than > half having ECC, and half having none, which has to be a better overall > solution, especially since there is no real redundancy in the original > datastream to allow errors to be "concealed". I'm not an expert on FEC at all. I have to rely on advice from other people and from open source found on the web on this. If you can point me open source code for either option, we can implement a modem for both these systems and simply try them out. For me, the codec2 gmskmodem project is as much about providing the possibility for people (including myself :--) to learn about all this and be able to actually experiment with this. > Graham Cheerio! Kr. Bonne. ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
