Thread: Good Omens
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Old 05-17-2020, 11:03 AM   #69
Quoth
Still reading
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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.
Quote:
Originally Posted by jbjb View Post
That's not correct, I'm afraid.
The Nyquist-Shannon theorem concerns the relationship between sample rate and signal bandwidth when sampling continuous-time signals. It's got nothing to do with distance.
I see they are now calling it Shannon-Hartley. Quite obviously from the context that's what I was referencing.
Go read it. It covers EVERY aspect of the signal channel. With more distance there is less signal. The Inverse Square law.
With less signal the signal to noise is worse, so mathematically you have to have less bits per symbol.
You can't easily have a bigger aerial or more power in the handset, so roughly you get a 1/4 speed when you double the distance.

The Nyquist frequency limit is what you may be thinking of. You have to sample at twice the highest frequency. The I & Q quadrature systems only seem to have a sample rate = max f, but because the samples are 90 degrees offset and there are twice as many samples, it's effectively twice the rate.

The names of these things vary:
SAMPLING https://en.wikipedia.org/wiki/Nyquis...mpling_theorem

Information Transmission https://en.wikipedia.org/wiki/Shanno...artley_theorem

Shannon Limit https://en.wikipedia.org/wiki/Noisy-...coding_theorem

So I'd rather watch Good Omens on HD Satellite than via streaming. But I might buy the disc when it's released.
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