PCM transmission system using codewords for difference values - has each codeword used for at least two successive difference values

摘要

The transmission system uses binary codewords for representing difference values, at least each two successive difference values transmitted using a common codeword. The classification of the codewords for the possible combinations of difference values is such that a bit error in a codeword gives a combination of difference values of the sum of which differs from that of the correct combination of values. Pref. to reduce errors the combinations of difference values are converted into different combinations, to which the codewords correspond, with a free codeword selected so that upon an error in the codeword of a frequently used combination the free codeword is obtained, which indicates the frequently used combination.