| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to decode a linear cyclic code in a small hardware quantity by repeating a specific recurrence formula by a polynomial calculation means until the degree of the polynomial becomes less than a specific value to calculate an error position polynomial and an error value polynomial and calculating a disappearance position polynomial from disappearance position data. SOLUTION: A polynomial calculating operation part 14 calculates an error position polynomialσ(x) and an error value polynomialω(x) by repeating respective recurrence formulaeσi=σi-2(x)+Qi(x).σi-1(x) andωi=ωi-2(x)+Qi(x).ωi-1(x) (provided that Qi(x) is a quatient ofωi-2(x)/ωi-1(x),σi-1(x)=1,ωi-1(x)=x2t,σ0(x)=1,ω0(x)=M(x) and M(x) is a corrected syndrom polynomial) until the degree of the polynomialωi becomes less than [(d+h-1)/2] (provided that [] is the Gauss' symbol, (d) is the minimum Hamming distance and (h) is the number of disappearance positions. Then, a disappearance position polynomialλ(x) is calculated from disappearance position dataαi.
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