The ShannonHartley theorem states that if the required information
transfer is less than the Shannon capacity limit (C), then error-free communication
is possible. If information transfer at a rate greater than C is attempted, then
errors in transmission will always occur no matter how well the equipment is designed.
The ShannonHartley capacity equation is a very good first step for evaluating the
feasibility of any digital communication system design. It immediately provides the
engineer with an 'upper bound' on channel capacity because it assumes a perfectly flat,
distortion and interference free communications link, with the noise taking the form of Additive White Gaussian Noise (AWGN). It also is a
theoretical bound with the implication that infinite signal processing power is available
in both TX and RX units. In practice, we will of course not be able to achieve data rates
quite as good as those suggested by the ShannonHartley equation, but it is a good
starting point in a design.
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