| 摘要 |
PURPOSE:To detect distance accurately even by a fine particle handling device which generates the ultrasonic wave of the same frequency as an ultrasonic wave for distance detection by providing an auxiliary receiver, an arithmetic unit, etc. CONSTITUTION:A gate 10 is opened with a transmitted gate signal D outputted by a control and arithmetic unit 9 to apply the output signal of an oscillator 12 to an ultrasonic wave speaker 3 through a transmission driver 11 for a constant time. Consequently, the ultrasonic wave A is transmitted from the speaker 3 to a surface 4 to be detected for the constant time. Then, the output signal (b+c) of an ultrasonic microphone 5 which detects both a reflected wave B and a shock sound C and the output signal (c) of an auxiliary ultrasonic microphone 8 are amplified by amplifiers 13 and 14 and then inputted to a differential amplifier 15, whose output is sent to a BPF16. Further, a comparator 17 compares the output level of the BPF16 with a constant reference level to detect the arrival of the reflected wave B at the microphone 5 and outputs a reception report to a device 9. The device 9 begins to clock the time while generating a gate D.
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