Is the random or pseudo-random manner of generating the tones or carriers an essential element of spread-spectrum? If so, and if the aim of using such a method is not to obfuscate the message but only to provide better immunity to interference and path variations, would you be any worse off using a repeated pattern of tones instead of a pseudo-randomly generated one? And if you did that, would it still be spread-spectrum?
Julian, G4ILO --- In digitalradio@yahoogroups.com, KH6TY <kh...@...> wrote: > > I can't fathom the reason for doing that, but if the tone frequencies > are pseudo-randomly generated and then modulated by either on/off keying > or some other way, you will have a spread spectrum system, similar to > what is done in the ROS 2200 Hz-wide modes. The tones in a ssb > transmitter simply generate rf carriers, so varying the tone frequencies > is no different than varying a vfo frequency as far as the outside world > sees. The distinction in spread spectrum is the generation of the tone > frequencies independently of the data. I.e., you first generate a tone > frequency in a psudo-random manner and then convey intelligence by > modulating the resulting rf carriers. > > 73 - Skip KH6TY
