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Apparatus for computing error correction syndromes

  • US 5,805,617 A
  • Filed: 11/25/1996
  • Issued: 09/08/1998
  • Est. Priority Date: 02/28/1996
  • Status: Expired due to Fees
First Claim
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1. An apparatus, for use in a Reed-Solomon decoder which decodes a codeword containing N received symbols, N being a positive integer, for calculating syndromes Si '"'"'s iteratively in N iterations, according to:

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    space="preserve" listing-type="equation">S.sub.i = . . . (r.sub.N-1 α

    .sup.i +r.sub.N-2) α

    .sup.i +r.sub.N-3 !α

    .sup.i +. . . +r.sub.1 α

    .sup.i !+r.sub.0wherein i is an integer ranging from 0 to 2T-1, T being a predetermined number, rN-j represents a jth received symbol which is fed in synchronization with a symbol clock, j being 1 to N, and α

    i denotes an ith root of a code generating polynomial, the apparatus comprising L syndrome calculating cells each of which provides K syndromes, each of K and L being a positive integer not larger than 2T, each syndrome calculating cell including;

    storage means containing a first set of K memory means, wherein the storage means sequentially provides contents of the first set of K memory means during each iteration and is initialized to 0 prior to a first iteration;

    first input means for sequentially providing K consecutive roots of the code generating polynomial during each iteration;

    a multiplier of a finite field GF(2m) for sequentially multiplying the K roots of the code generating polynomial provided from the first input means with the contents of the first set of K memory means provided from the storage means, to thereby provide K multiplication results during each iteration; and

    an adder on the finite field GF(2m) for adding the jth received symbol rN-j to each of the K multiplication results during each iteration, to thereby provide the K intermediate values to the storage means during a (j1)th iteration, j1 being 1 to (N-1), or provide the K syndromes to the storage means during an Nth iteration.

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