| 摘要 |
PURPOSE:To prevent surely a miscorrection without decreasing information bits by adding a vertical parity bit to the data which correct an even number of errors after adding a redundant bit to the information bits converted into blocks. CONSTITUTION:A redundant bit 2 or 8 bits is added to an information bit 1 of 7 bits together with a vertical parity bit 3. Thus the code length of 16 bits, an information bit 7 and a correction capacity bit 2 are obtained. The data are transmitted with BCH (16, 7, 2) codes of a structure having an inter-code distance 6. In other words, the information bit Q(x) is divided by a polynomial G(x) to obtain the residual R(x) equal to a redundant bit 2. Then a vertical parity 3 shown by P=Q(x).X<8>+R(x) is added to the bit 2 for transmission. At the reception side the vertical parity P is divided by the polynomial G(x) to obtain a syndrome for correction of errors up to 2 bits. When an error of >=3 bits is decided, the bit Q(x) is applied as data without giving any correction.
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