| 摘要 |
PURPOSE:To obtain an absence correcting and decoding method which is high ability in correction by setting a recurrence formula which is specific for the general form of the coefficient term of a specific formula so that each error pattern is derived from the specific formula, and varying the address of a rewritable memory part successively in every cycle and also controlling the memory part in the order of reading and writing. CONSTITUTION:An error pattern eiN is expressed by I and its denominator consists of a combination of (N-1) terms shown in II and is calculated relatively easily. The numerator of the equation I is larger in the under of combinations of coefficients zetaN-1.delta and its calculation is considerably complicated. Then when the general form of the coefficient zetan-1.delta of the denominator of the equation I is zetap.q, a recurrence formula III is obtained for the general from zetap.q of the terms zetaN-1.delta, so a coefficient zetaN-1.q of each term of the numerator of the equation I is calculated efficiently from the coefficient zetaN-1.delta-1 right before it. Consequently, the calculation of the equation I, i.e. error pattern eN is found speedily. Thus, the numerator of the equation I is calculated on the basis of data zetaN-1.1...zetaN-1,n-1 stored in the memory part 23 to calculate the error pattern eN efficiently and speedily from the recurrence formula III.
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