| 摘要 |
PURPOSE:To make it possible to easily inspect the damage of an optical disk, by providing a gate for selecting a counter being supposed to perform counting on the basis of the signal from a damage length setting part, a counter for counting the number of damages with a set length and a total number counting part for storing the count value of the counter. CONSTITUTION:A damage length setting part applies a clock signal A for setting a reference value of a damage length to comparators 1-3 and set the reference value of the damage length on the basis of latch signals B-D. Next, the counters 7, 8 of the damage length judge part compare a damage length resolving power clock signal F with the damage length signal from a measuring head to measure the length of damage. The measured signal is sent to the comparator 1 at first and, if the length of the damage is within the range set by the comparator 1, a signal N is emitted from a counter 8 and a counter 4 comes plus 1. If the length of the damage is out of the range set by the comparator 1, the counter does not count and a gate 9 is opened by the signal from the counter 2 and a counter 5 comes to plus 1 by the signal N. By this method, the counters 4-6 successively count the number of damages and the count values are stored in memories 11-13 each time and the stored values are read by an external signal G.
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