| 摘要 |
PURPOSE:To read exactly data recorded in unit of row for each row by arranging discriminating data to distinguish whether the row is a even number-th row or odd number-th row in each row of data. CONSTITUTION:A row of discriminating data bits S is provided between a row of bits R and an area Q. The row of bits S has information to discriminate whether the row of data is even number-th row or odd number-th row. The information can be expressed by data of 1 bit at a minimum. However, it is expressed by two bits, S1, S2 in this case. That is, odd number is expressed when S1=1, S2=0, and even number is expressed when S1=0, S2=1, and an error is expressed by other combination. For instance, supposing that reading is made at reading positions A, B, C, as S1=1, S2=0 at reading positions A and B, it can be recognized that the reading signal belongs to a row of odd number. As S1=0, S2=1 at the reading position C, it can be recognized that the reading signal belongs to a row of even number.
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