On Saturday 09 January 2010 10:06:13 am David Kleber wrote: > > [can anyone explain "Long receive integration"?] >
MT63 data is spread in both the frequency domain and the time domain. Long interleave lengthens the time domain spreading from 32 to 64 bits (hence the term long), and because of this longer time spreading, the effects of short fading or noise bursts are minimized. The spreading over a longer time period allows decodable data to actually be present after the interference that would otherwise have affected the data reception accuracy. The flip side is that the data takes longer to come across at the end of the typing. You'll see MT63 still sending tones long after you quit actually typing. This is real data and you shouldn't cut the TX short. This is because the time delays through the encoder and decoder are both longer. If you think forward error correction, you will have some idea how this works. It isn't forward error correction, at least not as we think of it in say PSK modes. But the concept might help understand what the longer time spreading is doing. Take a look at this and see if it helps: http://www.qsl.net/zl1bpu/MT63/Technical.htm Rick Kunath, k9ao _______________________________________________ fldigi-alpha mailing list [email protected] https://lists.berlios.de/mailman/listinfo/fldigi-alpha
