Patent Document ID: 6131178
Application ID: 09034340
Patent Flag: 1

Claim One:
1. An error correcting decoding apparatus of an extended Reed-Solomon code comprising: syndrome generating means for computing from an incoming received word its syndrome; received word memory means for storing said received word; error number estimating means for estimating a number of errors having occurred in said received word from the syndrome computed by the syndrome generating means; Euclidean algorithm computing means for computing an error-locator polynomial and an error-value polynomial by Euclidean algorithm after setting initial values and an ending condition for computing the error-locator polynomial and the error-value polynomial in accordance with the number of errors estimated by said error number estimating means; Chien's search means for computing error locations and error values based on the error-locator polynomial and the error-value polynomial computed by said Euclidean algorithm computing means; and error correcting means for correcting errors of said received word stored in said received word memory means in response to a result computed by said Chien's search means, wherein said error number estimating means comprises a memory, multipliers and adders on a Galois field, and makes a decision, about an extended Reed-Solomon code with a minimum distance of d, from values of the syndrome of said received word, which is computed by said syndrome generating means, whether any error is present or not, and if any error is present, whether a number of the errors is less than ((d-1)/2) or equal to ((d-1)/2), and wherein said Euclidean algorithm computing means computes the error-locator polynomial and the error-value polynomial by Euclidean algorithm after setting the initial values and the ending condition for computing the error-locator polynomial and the error-value polynomial depending on the number of errors whether it is less than ((d-1)/2) or equal to ((d-1)/2), when said error number estimating means makes a decision that the error is present.