APPARATUS FOR DETECTING AND CORRECTING ERRORS IN PRODUCT CODES FOR ERROR CORRECTION IN DIGITAL INFORMATION DATA TRANSMISSION OR RECORDING SYSTEMS

摘要

ABSTRACTThe present invention provides apparatus for detecting and correctingerrors in product codes of minimum distance 2t, with t being a positiveinteger, wherein, with respect to information of (kx?) symbols arranged in amatrix with k rows and ? columns, with k and ? being positive integers, in eachof k rows a checksum symbol is added constituting codes with minimum distance 2to ?, and in each of (?+1) columns including a column for said added checksumsymbols, a set of parity check symbols are added constituting codes of minimumdistance to k symbols. The apparatus performs a first decoding of (?+1) codesin column-direction by means of a first decoder, then decides the decoding modeamong three decoding modes by statistical processing of the error number flagsissued from the first decoder, and finally performs a second decoding in which,responding to the decided decoding mode, the decoding is made as assertion ofsimple error detection, or single erasure error correction by using codes inrow-direction, or error detection by using codes in row-direction. The systemis especially suited for use in parity checking in digital information datatransmission or recording, where high speed and reliability are required.