Error detection and correction using two error correction stages

摘要

An arrangement is described, which detects and corrects data, comprising a first error detecting and correcting stage (114) having a predetermined error detection and correction capability determined by the number of errors it can detect and correct in a data stream of predetermined length, and a second error correcting stage (116) for receiving data from said first stage (114), the first stage (114) being arranged to receive a data stream of predetermined length, determine the number of known errors in the data stream and correct any such known errors if it is possible within its error detection and correction capability, detect and correct any unknown errors if it is possible within its capability, and output data providing an indication to the second stage (116) of an error state relative to said data stream, the error state being one of a plurality of states including a first state indicating that there are no known errors in the data stream or that the first stage (114) has corrected all known errors in the data stream using less than its predetermined error correction and detection capability, a second state indicating that the number of errors in the data stream exceeds its capability and could not be corrected, and a third state indicating that all known errors in the data stream have been corrected using substantially all of its capability.