| 摘要 |
PURPOSE:To reduce the size of a range finder by providing calculating means for being inputted with detecting and driving timing signals and obtaining range between a piezoelectric vibrating plate and a target on the basis of time lag between the instances when both the timing signals are oscillated. CONSTITUTION:When a range is measured by an ultrasonic wave type range finder, driving timing signal oscillator means 1 oscillates driving timing signal A. The signal A makes driving ultrasonic signal oscillator means 2 oscillate driving ultrasonic signal B and, at the same time, actuates the timer of calculating means 9. The signal B is fed to a piezoelectric vibrating plate 3 to vibrate it, which emits ultrasonic wave to an object 4 to be measured. The vibrating plate 3 that is vibrated by the ultrasonic wave reflected from the object 4 produces ultrasonic current, which is converted to detecting timing signal D via an amplifier 6, a rectifier 7 and a waveform shaper 8. The calculating means 9 calculates range L between the vibrating plate 3 and the object 4 on the basis of time lag between the signals A and D. Thus, the size of a range finder can be reduced.
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