Image Number 7 for United States Patent #3938085.
The transmitting station comprises coding means, including a shift-register having L stages, where L is the length of the code, for delivering continuation and repetition bit trains, each of which comprises information bits including at least L message bits as well as the parity bits associated with the information bits. In the case of a continuation bit train, the L message bits are supplied by a data source, in the case of a repetition bit train, they are fed back to the coding means from the shift-register. In the receiving station, the decoding of messages bits is a conventional decoding in accordance with the code where a continuation bit train is concerned, but also takes into account the previously decoded value where a repetition bit train is concerned. The trains may be identified by mean of prefixes of N.sub.1 bits, in which case, each bit train comprises (N.sub.1 + L) information bits.