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The Shannon-Hartley Theorem
(AKA Shannon's Law)

  • First proposed by Ralph Hartley

  • Proved by Claude Shannon in Communication in the Presence of Noise (Proc. Institute of Radio Engineers, vol. 37, no.1, pp. 10-21, Jan. 1949)

  • Specifies the theoretical limit on the amount of information that can be transmitted via a communications channel (e.g. a radio link)

C = BW x log2(1 + SNR)

where:

C = Capacity of a communications channel in bits per second (also known as the Shannon Limit)
BW = Bandwidth of the channel in hertz (available spectrum minus allowance for filter rolloff and guard bands)
SNR = Signal-to-noise ratio of the channel