Base on shannon capacity limit,what are the possibility of transmitting
information when the signal is lower than the noise?
thks for any help that is being provided for the above question.
elite wrote:
Base on shannon capacity limit,what are the possibility of transmitting
information when the signal is lower than the noise?
thks for any help that is being provided for the above question.
Why not plug the numbers into the channel capacity equation, and see?
Steve
Base on shannon capacity limit,what are the possibility of transmitting
information when the signal is lower than the noise?
thks for any help that is being provided for the above question.
... (speeling not gauranteeded.)
Steve Underwood wrote:
elite wrote:
Base on shannon capacity limit,what are the possibility of transmitting
information when the signal is lower than the noise?
thks for any help that is being provided for the above question.
Why not plug the numbers into the channel capacity equation, and see?
Steve
In that case where the signal power is lower than the noise power,
shannon capacity is represented as
C = log2( 1 + SNR)
where SNR = P_s / P_n < 1. This means that up to SNR is 0, there is a
way to transmit the information of which the transmission rate is less
than C.
FWIW ??
you know those beautiful photos of Jupiter, Saturn, Uranus, and Neptune
that Voyager 1 & 2 were sent from a 20 watt transmitter (with a pretty
good beam antenna) over billions of kilometers of distance (run the
inverse-square law on that one!) and both space and our atmosphere are
known to be pretty noisy. i think the S/N ratio was many dBs below 0.
yet we got them beautiful photos. (it might have taken days to receive
and decode the data.)
beside "Spread Spectrum" (as was mentioned), also look up "Reed-Soloman
Coding". (speeling not gauranteeded.)
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