Isn't this really about how legacy FM radio can be used with codec2 in a simple way?
Just to add to the confusion, couldn't a simple n/m bit encoding be sufficient? If we take 8b/10b coding, it has some interesting characteristics. i) There are enough transitions to enable good clock recovery ii) There is a maximum run length of same bit, in effect forcing a minimum frequency to the signal. iii) out of the possible 1024 symbols just 256 are used for data, leaving a lot for control iv) It is simple to encode / decode ( just lookup tables) v) it is 80% efficient vs NRZ (8/10) With the low codec2 bitrate, it should give ample margins for decoding. The benefits of something along these lines is that almost all legacy AND modern radios would be compatible, althought IF filters would be suboptimal, unless replaced. Using a "baseband coding" the bit shape could be adjusted using a simple FIR filter, again in a very simple microprocessor or in a shift register for that matter (aka G3RUH). With careful deviation adjust it could be GMSK. Just my 2 c worth, Gullik ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
