公开(公告)号：JP2000224049A

公开(公告)日：2000-08-11

申请号：JP1346899

申请日：1999-01-21

Applicant: IBM

Inventor： NAKAMURA AKIO ,  TAMURA TETSUYA ,  DEMURA MASAYUKI

IPC: G06F11/10 ,  G11B20/18 ,  H03M13/00 ,  H03M13/15

Abstract: PROBLEM TO BE SOLVED: To detect error correction in a short time and to execute error correction by adding an error correction code to one or more error detection code blocks to which the error detection code is attached, calculating an error value by using the error correction code respectively included in data series, correcting the syndrome value of the error detection code according to the value and detecting error occurrence. SOLUTION: A selector 126 operates in accordance with the control of a chain searching part 112 of an error correction block 10 and selects a root inputted from a position counter 110, when it is shown that there is no error in detected data. Then, it outputs it to error detection code EDC correction difference calculating parts 14a and 14b and a syndrome correction difference calculating part 18. A selector 128 operates in accordance with the control of the part 112 of the block 10, selects a numerical value 0 when it is shown that an error does not exist in detected data, selects size data when an error exists in the detected data and outputs to the parts 14a and 14b.

公开(公告)号：JPH08293802A

公开(公告)日：1996-11-05

申请号：JP8850495

申请日：1995-04-13

Applicant: IBM

Inventor： NAKAMURA AKIO ,  MURAKAMI MASAYUKI ,  NUMATA TSUTOMU

IPC: H03M13/27 ,  H03M13/29 ,  H04L1/00 ,  H03M13/22

Abstract: PURPOSE: To correct further large amounts of errors by suppressing the increase of a check symbol part to the absolute minimum, and unnecessitating error position information from the outside by operating encoding by a crossing method using two codes whose design distance is different. CONSTITUTION: An encoder 12 of a device 10 converts a digital data input into the stream of symbols being the constituting elements of a code word, the re-arrangement of a sequence is executed by an interleave controller 14, and a code part is calculated for each system. Then, an individual system in which information blocks are crossed by a crossing method is obtained. One system is selected from among (k) pieces of systems, and a check symbol which is longer than that of the other systems is added to the selected system. As a result, one system whose design distance is (d2 +1) and (k-1) pieces of systems whose design distance is (d2 +1) are formed. When correctable continuous errors with less than length (t)1 are detected in the decoding process of the system 1, it is assumed that an error is generated at the adjacent code position in the other system, and this adjacent position is defined as an annihilation trace and handled in the following processing.

公开(公告)号：JP2000020333A

公开(公告)日：2000-01-21

申请号：JP18482798

申请日：1998-06-30

Applicant: IBM

Inventor： NAKAMURA AKIO ,  TAMURA TETSUYA ,  DEMURA MASAYUKI ,  NAGURA HIROHISA

IPC: G06F11/10 ,  H03M13/01 ,  H03M13/15

Abstract: 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 polynomial σ(x) and an error value polynomial ω(x) by repeating respective recurrence formulae σi=σi-2(x)+Qi(x).σi-1(x) and ωi=ωi-2(x)+Qi(x).ωi-1(x) (provided that Qi(x) is a quatient of ωi-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 polynomial ωi 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 polynomial λ(x) is calculated from disappearance position data αi.

公开(公告)号：JP2001044853A

公开(公告)日：2001-02-16

申请号：JP18156299

申请日：1999-06-28

Applicant: IBM

Inventor： KATO KATSUHIKO ,  NAKAMURA AKIO ,  TAMURA TETSUYA

IPC: G06F11/10 ,  G11B20/18 ,  H03M13/15

Abstract: PROBLEM TO BE SOLVED: To provide a chain search circuit that shourtens the time required for chain search without having to increase the number of gates of a multiplication result storage circuit, when conducting pipeline processing for quickening chain search. SOLUTION: A chain search circuit 55 is provided with flip-flop circuits(FF) 101a to 101c, that are provided corresponding to each term of an error location polynomial, store each coefficient of the error location polynomial for an initial value and store a multiplication result of multiplying an element of a Galois field with each coefficient, high-order fixed multipliers 103a to 103c that multiply the powers (αn) of the highest order αrespectively in parallel corresponding to the flip-flop circuits(FF) 101a to 101c, and low order fixed multipliers 104a to 104c that respectively multiply the powers (αn-1) of the lower order α, and the flip-flop circuits (FF) 101a to 101c latch only the result of products of the high-order fixed multipliers 103a to 103c that multiply the powers (αn) of the highest order α.