| 摘要 |
<p>PURPOSE:To perform 8/9 information rate conversion in which the continuation of binary value ''0'' is lessthan 4 and the length of error propagation is short by converting the binary 8-bit codes to 9-bit codes according to logical combinations of specified bits. CONSTITUTION:When the upper 4 bits X1 and X2, Y1 and Y2 of 8 bits binary data codes X1, X2, Y1, Y2, Z1, Z2, Z3, Z4 are combined by logic circuits, the coding condition signals a1 thru a3 according to the combinations are determined. When these signals a1 thru a3 and the binary codes of the respective bits are processed in AND circuits 10 thru 15, OR circuits 17 thru 20, the binary codes of 8 bits are subjected to 8/9 information rate conversion to 9 bits binary codes of repective bits C1 thru C9 based on the formulas I, II with the simple constitution. The 9 bits binary codes thus converted are restricted in less than 4 in the continuation of binary value ''0'' and may be made to the codes of a short error propagation length. Decoding is also readily accomplished in a similar manner.</p> |
