Method and apparatus for encoding/decoding n-bit data into 2n-bit codewords

Abstract

The present invention relates to the encoding and decoding. respectively, of serial data, using block codes. Encoding of a serial bit stream of input data in groups of N bits, so-called words (O), to serial output data in groups of 2N bits, so-called code words (KO), is preferably carried out by a logic circuit in a manner such that N of the 2N bits in the code words (KO) are comprised of the N bits input data, unchanged or inverted, and remaining bits in the code words (KO) are determined so that, seen statistically, the code words (KO) will include approximately as many zeros as ones, such that each code word (KO) will be unique for each word (O), and such that at least one of the code words (KO) will remain unique even in bit stream shifting processes. Decoding includes further encoding in a similar logic circuit and comparison of the incoming code words with the code words encoded in the logic circuit, in a predetermined manner.