| 摘要 |
<p>PURPOSE:To output a prescribed detection signal only when a body to be detected is a moving body by detecting whether or not the body is the moving body from variation in the reception time interval of a reflected light from the body to be detected. CONSTITUTION:If the body to be detected enters a sensing range A while an ultrasonic wave from an oscillation-side vibrator 3 is outputted into the sensing range A through the operation of an ultrasonic wave oscillator 1, the reflected wave from the body is inputted to a reception-side vibrator 4. Then the reflected wave is amplified 5 and then passed through a limiter 7 and an envelope detector 8 to remove its ultrasonic wave component. A reflected wave signal SG4 outputted by the envelope detector 8 is integrated by an integrator 9 and outputted as an integral signal SG5 to a modulation detector 11. The modulation detector 11 compares the input integral signal SC5 with a last input integral signal SG5 in each period C. Then when their difference is detected, it is decided that the body is the moving body and a detection signal SG6 is outputted to a multivibrator 12.</p> |
