Murray.pa@Xerox.ARPA (08/30/85)
From: Murray.pa@Xerox.ARPA From Michael Chepponis: "High-speed" here means 56 kb/sec, because that is the maximum rate allowed on 220 and 440 bands; really high-speed stuff will have to be on 1240 MHz. Can somebody explain the reason for that constraint? (I know that "reason" and regulations frequently don't make sense.) I'd expect that the restriction would be on bandwidth rather than bit rate, and Shannon tells us that the signal/noise ratio as well as the bandwidth is what actually constrains the bit rate. Are there some theoretical limits on S/N that I've missed? (Like max output power and receiver front end thermal noise?)