On Jan 3, 2005, at 5:07 PM, Dave Close wrote:
Jim Thompson wrote:"There will always be more capacity in a wire."
While I understand your point, Jim, keep the philosopher's comment in my signature in the back of your mind.
Point-to-multipoint transmissions, aka broadcast, if measured at the receivers would greatly exceed the capacity of any known wire.
Only if you assume < 3 parties on the wire. :-)
In your broadcast model, its the same information to all receivers, so rate of information transfer is that of two parties anyway.
And in any case, channel capacity in a wire over a given distance will (ahem, cough cough) "typically" be greater
than a wireless link over the same distance.
If we had such a thing as an infinite-bandwidth, noise-free analog channel we could transmit unlimited amounts of error-free data over it per unit of time. However real life signals have both bandwidth and noise-interference limitations.
Bandwidth limitations alone do not impose a cap on maximum information transfer because it is still possible (at least in theory) for the signal to take on an infinite number of different voltage levels on each cycle, with each slightly different level being assigned a different meaning or bit sequence. Add noise, and you're constrained by the Shannon theorem: C < W log (1 + SNR)
