| 摘要 |
PURPOSE:To enhance distance measuring capacity using an ultrasonic wave by correcting ultrasonic wave propagation loss and making it possible to measure a wide range of a distance, by increasing the amplifying degree of a signal amplifier in synchronous relation to a main oscillation part over time. CONSTITUTION:An ultrasonic wave is transmitted from a transmission part 3 driven by a pulse wave synchronous to the fundamental timing from a main oscillation part 1 and the ultrasonic signal reflected by an reflecting article 10 and returned therefrom is received by a receiving part 4. The received ultrasonic signal is amplified by a signal amplifier 5. An amplifier control circuit 6 operates in synchronous relation to the main oscillation part 1 and allows the amplifying degree of the signal amplifier 5 to increase over time. That is, the amplifier control circuit 6 adds the correction function of the propagation loss of the ultrasonic wave to the signal amplifier 5. The signal outputted by the signal amplifier 5 is detected by a detector 7 and the distance up to the reflecting article 10 is operated by a signal processing part to be displayed on a display part 9.
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