| 摘要 |
A device is provided for encoding a stream of data bits of a binary source signal (S) into a stream of data bits of a binary channel signal (C1), wherein the bit stream of the source signal is divided into n-bit source words (x1, X2). The device includes converting means adapted to convert the source words into corresponding m-bit channel words (y1, y2, y3). Each n-bit source word together with another n-bit source word forms a pair of source words. The values of the n-bit source words differ only in the value of the bit in the q<th >bit position, q being a constant. The pairs of source words are divided into a first part of pairs and a remaining part of pairs. The converting means are further adapted to convert n-bit source words belonging to the first part of pairs into corresponding m-bit channel words, in such a manner that the conversion for each of the n-bit source words is parity preserving, and to convert n-bit source words belonging to the remaining part of pairs into corresponding m-bit channel words, in such a manner that the conversion for each of the n-bit source words is parity inverting. A decoding device is also provided for decoding the channel signal obtained by means of the encoding device.
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