On 01.11.2011 22:42, Kristoff Bonne wrote: > (I know this is a bit dangerous discussion as there are some people > who think that other (non-D-STAR compatible) DV modes would hinder > the further growth of D-STAR. I understand their concerning, but I > do like people to be able to experiment).
In the actual stage of codec2's development the whole FEC/Modem discussion is far too early. In my opinion codec2 should be fully developed and investigated until it can compete with other commercial voice codecs or even outperform them. This is evolution - it has nothing to do with "hindering progress": apparently the opposite is true - biologically speaking, we will observe surviving of the fittest :-) >> A good start for adding FEC to Codec 2 is to test the effect of bit >> errors on each bit. Not all bits need protection. So strong codes >> can be used to protect the most sensitive bits, leaving some bits >> unprotected. > > So, what FEC protocol do you propose? Are there 1/2 FEC protocols out > there that are not patented? FEC is something the modem has to cope with: HF faces other difficulties than Internet based VoIP applications. For example using turbo codes for FEC will help us achieving near shannon-limit capacity - but it is not free from patents for non amateur radio usage. > The gmsk demodulation does 103 multiply-and-add per audio-sample > (sampling at 48000 Khz). Why stick with gmsk - personally I suggest an OFDM modem with well-chosen parameters to meet HF, VHF or microwave link requirements. Let me sum up: this project is a great way to promote the science of amateur radio communication and open source... Regards, Andreas Weller ------------------------------------------------------------------------------ RSA® Conference 2012 Save $700 by Nov 18 Register now! http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
