| 摘要 |
PURPOSE:To secure a use of a pair of ultrasonic elements both for the transmitting and receiving waves and at the same time to simplify the constitution of a range finder, by closing a receiving wave gate for a prescribed time after oscillation of an intermitted ultrasonic wave and latching the count value of a counter that starts at the time of oscillation via the wave receiving signal. CONSTITUTION:A mono-multi is triggered by an intermitted ultrasonic wave, and an analog gate is closed by an ultrasonic element for a period during an ultrasonic wave is transmitted. A counter circuit that counts the clocks starts at a rise time of the output of the mono-multi. The count value of the counter circuit is latched at a latching circuit by a received wave signal sent through an analog gate and a threshold value deciding circuit. The heat generation of an ultrasonic element is prevented by an intermittent oscillation and with a simple constitution using an ultrasonic element which is used for both transmission and reception of the wave. Meanwhile a highly efficient range measurement is possible with a small amount of energy. |
