Patent Document ID: 4727547
Application ID: 06753255

Base Claim:
1. A method for transforming a first sequence of words, comprising digital data words and correction words and having a first ordering of said data words and correction words, comprising the steps of: forming blocks out of said first sequence, each block consisting of a plurality of said data words and a plurality of said correction words in said first ordering; selecting data words and correction words from said first sequence and combining said data words and correction words in a way to form a second sequence with a second ordering of data words and correction words; selecting out of the second sequence of words a first group and a second group each composed of data words and correction words in such a way that said first group and said second group (share) have one common word (with one of said blocks of words having the first ordering) and said common word also belongs to one of said blocks composed of words having said first ordering; submitting simultaneously the data words of the first group and of the second group to a checking operation; evaluating the result of the checking operation and deciding if erroneous data words of the first group and of the second group can be corrected; and correcting said second sequence of words using said correction words, when indicated by said evaluation.

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Claim 4:
4. Method according to claim 1, comprising the steps of: adding a block error detection code word to the blocks of said first sequence prior to transforming said first sequence; for transforming said first sequence, first checking said blocks of said first sequence with respect to said block error detection code by generating again a code word and comparing it with the existing code word; adjoining a block flag to each block of the first sequence composed of data words and correction words according to the results of said checking with respect to the block error detection code, said block flag marking erroneous and error free blocks; and deriving word flags from said block flags for the data words and correction words of said blocks, said word flags being set for a group of word preceeding said group of data words and correction words already under checking and evaluation operations.