Jim, You make some good points. Frank also mentioned the PLL which I haven't had time to check out yet, but I will. Also the PSK31 algorithm may be a good choice.
Thanks, Steve -------------------------------------- Given that the received signal will be varying in frequency (due to drift in the Tx and a Hz or so of ionospheric uncertainty), something like a PLL might be a good choice. Fairly low CPU load (especially if you're feeding in a decimated signal at low sample rates). You might look at the algorithms being used in PSK31 decoders, which also have a form of AFC and/or PLL to track the input signal as it moves around. I haven't looked, but I'll bet there's some literature out there on building optimal filters for morse decoding. For instance, you could also track sending rate, and build a "dot filter" and "dash filter" optimized for the two lengths of pulse. You could also do some sequential decoding to do a better job decoding the characters (that is, essentially look for entire characters, rather than just dots and dashes). _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
