| 摘要 |
PURPOSE:To facilitate inventory control by providing a pulse width clocking means which starts counting clock pulses in response to each pulse in an input pulse train and outputs a constant-width pulse continuously until the counted value attains to a preset value. CONSTITUTION:The pulse width clocking means 37 is supplied with the set value previously by a pulse width setting means 38 on the basis of the forecasted repetitive period of the input pulse train P11. the means 37 inverts the output to output the constant-width pulse PC during use every time each pulse of the pulse train P11 is applied to the means 37. This pulse PC lasts until the clock pulse P10 applied to the means 37 reaches the set value which is given previously, and the pulse PC is inverted when the pulse P10 reaches the set value, so that the pulse PC is not outputted any more. Thus, the pulse PC is outputted every time each pulse of the pulse train P11 is applied to the means 37, so the impact ratio of a constant-width pulse train P12 varies with the frequency of the pulse train P11 and variation in the impact ratio is detected 4, so that an LPF 4 outputs an output signal S13 corresponding to the impact ratio.
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