| 摘要 |
PURPOSE:To calculate a highly reliable and accurate measured value without receiving the effect of noise due to the change in a circumferential condition, by directly receiving the ultrasonic wave transmitted from a target to measure a distance. CONSTITUTION:The pulse like ultrasonic waves transmitted from a target 1 at a definite cycle are indivisually received by a plurality of receivers S1-S2. Time difference pulses (h)-(m) each showing the time difference from transmission to reception are sent out in corresponding relation to the receivers S1-S2 corresponding to receiving outputs (c)-(g) by the operation synchronous to the definite cycle of a transmission side in a receiving part 3 and a clock pulse CLK is counted on the basis of a synchronous pulse (b) by a count group 6 and the indivisual distance up to the target 1 is calculated corresponding to either one of combination pairs in the time difference pulses. An operation part 7 averages the indivisual distances calculated on the basis of each combination to calculate the accurate distance having high reliability up to the target.
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