| 摘要 |
PURPOSE:To realize an efficient decoder for a quadruplex error correction BCH code by employing a method of solution for a quartic equation of a Galois field and a method of solution which solves even less than a cubic equation by referring it to a quartic equation. CONSTITUTION:The decoder for quadruplex error BVH codes which uses an ROM represents elements by exponents and also represents elements of degree 0 which use the exponents 0, 1...2<m>-2 all by 1, i.e. (111...1). Circuits CG6 and CG7 are circuits which calculate coefficients of an error position polynomial. When A=S1(S<5>1+S5)+S3(S<3>1+S3)not equal to 0, an SWC.8 is placed at the upper side to decide on that there is a one or two-bit error. Then, the error position polynomial is regarded as a quartic equation to calculate coefficients sigma4i (i=1, 2, 3, and 4). The circuit CG1.6 is a circuit which calculates sigma22 from sigma22=(S<3>1+S3)/S1 and the CG2.7 calculates the sigma42, sigma43, and sigma44. |
