| 摘要 |
PURPOSE:To detect blip marks accurately with a set of sensor by generating a detection signal of the blip marks at the point of the time when the number of pulses generated at specified time intervals attains a prescribed value. CONSTITUTION:Clock pulses (c) are generated from an NAND gate GA1 corresponding to a high level signal detecting blip marks of prescribed lengths through a sensor from a terminal B and the synchronizing pulses proportional to film speeds and the blip marks are detected with FF1-FF4 of D type FFs of 4 stages or the like responding to the fall of the input pulses. The erroneous detection by dust, etc. shorter than the blip marks is prevented by such constitution whereby the detection outputs for the blip marks are generated after lapse of the specified time by the prescribed number of pulses according to film speeds and blip mark lengths, and the blip marks are detected accurately with a set of sensors. |
