Efficient Coding

This paper reviews briefly a few of the simpler aspects of communication theory, especially those parts which relate, to the information rate of and channel capacity required for sampled, quantized messages. Two methods are then discussed, whereby such messages can be converted to a “reduced” form in which the successive samples are more nearly independent and for which the simple amplitude distribution is more peaked than in the original message. This reduced signal can then be encoded into binary digits with good efficiency using a Shannon-Fano code on a symbol-by-symbol (or pair-by-pair) basis. The usual inefficiency which results from ignoring the correlation between message segments is lessened because this correlation is less in the reduced message.