| 摘要 |
PURPOSE:To obtain a detecting device which has the sufficient ability to detect an obstacle in a near area behind an automobile by providing an ultrasonic wave transmitter and receiver which has a turntable at one end of the rear part of the automobile and also providing an ultrasonic wave receiver at the other end. CONSTITUTION:The ultrasonic wave transmitter and receiver 2 and its turntable 3 are provided at one right or left rear end of the automobile and the ultrasonic wave received 4 is provided at the other end. The transmitter and receiver 2 is equipped with an ultrasonic sensor 2a of relatively low frequency and an ultrasonic sensor 2b of relatively high frequency. When detection is performed relatively nearby behind the automobile, the sensor 2a of the transmitter and receiver 2 transmits ultrasonic pulses under the control of a microprocessor 6 and the pulses are received by the receiver 4 to decide whether or not there is a body by analyzing the waveform of the received wave. When the detection is performed in a relatively distant area behind the automobile, on the other hand, the sensor 2b of the transmitter and receiver 2 transmits ultrasonic pulses and the transmitter and receiver 2 receives the reflected wave pulses to decide whether or not there is a body by taking a time analysis of the received wave.
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