The term "Spread Spectrum" can apply to any mode that spreads its energy over
more than the necessary bandwidth. If we assume the necessary bandwidth to be
equal to the signalling rate than anything other than single carrier modes
technically fall into this category.
Even WSPR coul dbe considered spread spectrum! Its 6Hz bandwidth is wider
than the 1.5 B/s rate. Within the WSJT suite, JT65 is more of a spread
spectrum mode, and outside Joe's suite, MT63 with its 2.5kHz for a few tens of
Bits / second is even more extreme.
Andy
www.g4jnt.com
