Method and device for the brief of a block of symbols of a code which is divided in two ways on the code words which are each protected by a code a maximum distance of separation

摘要

A block of code symbols is protected by a product code or a pseudo product code. First of all, all syndrome symbols are formed and all code words having a syndrome which deviates from zero are provided with a flag. Each non-redundant symbol forms part of a first code word and also of a second code word, the numbers of flags of first and second code words being separately summed. The code words are successively addressed and an error location is determined. When an error location forms part of an incorrect first code word as well as of an incorrect second code word, it is corrected; if the second code word is not signalled as being incorrect, however, the error will not be corrected. After correction, the syndromes are updated, the flags being updated and the summing results being decremented only if the syndromes of both relevant code words are zero. In the opposite case the flags will remain unmodified for the time being.