| 摘要 |
PURPOSE:To obtain a defect detection signal having good time accuracy free from time delay by generating a defect detection signal having a leading edge precedent to the leading edge of a defect input pulse and having a trailing edge at or after a trailing edge. CONSTITUTION:When a defective part is read, and an input pulse is supplied, period of the input pulse is measured by a period detecting means, and a term T shorter than the period of the input pulse by a specified short time is set by a term setting means. A point of time after lapse of time corresponding to the set time T from a leading edge time of the input pulse is set as the leading edge time of an output pulse by a pulse leading edge setting means. A point of time after lapse of specified time from a point of time of rear end of the first input pulse after a time set as a leading edge time of the output pulse or from a point of time set as a leading edge time of the output pulse is set as a trailing edge time of the output pulse. Then, the output pulse of an output pulse generating means is sent out as a defect detecting signal.
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