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Originally Posted by Quoth
You are mixing up two things. The law on information is often simply called Shannon's Limit. The Sample rate issue is usually called the Nyquist Limit.
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No, I'm not mixing up anything. The Nyquist-Shannon theorem refers to sampling rate and bandwidth:
(See
https://en.wikipedia.org/wiki/Nyquis...mpling_theorem)
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I see they are now calling it Shannon-Hartley. Quite obviously from the context that's what I was referencing.
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Shannon-Hartley is indeed more relevant, but again even that doesn't mention distance. Shannon-Hartley theorem defines channel capacity in terms of signal to noise ratio. The SNR may indeed fall off with the square of distance in most cases, but when you make claims about "EVERY WIRELESS system" (your capitalisation) you need to be a bit more careful. In the presence of non-isotropic transmitters, beam-forming, collimated beams, focused beams etc. etc. that's not necessarily the case. Even in the cases which are inverse-square, the effective origin of the beam isn't necessarily physically coincident with the transmitter, so in terms of distance from the transmitter the performance can be much better than inverse square.
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It covers EVERY aspect of the signal channel.
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You're being a bit over-free with the "EVERY" - Shannon-Hartley doesn't cover everything.
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With more distance there is less signal. The Inverse Square law.
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Not necessarily inverse-square, as discussed above.