| 摘要 |
PURPOSE:To decide the distance to the obstacle, hearing a sound of alarm in the car, and drive a car in case when a driver moves it backward, by emitting an ultrasonic wave from an obstacle detection part installed in the rear body of the car, and receiving a reflected wave from the objective obstacle. CONSTITUTION:The obstacle detection part 2 is provided in the rear body of a car, an ultrasonic wave is generated by its ultrasonic transmission part 5, and the ultrasonic wave modulated by a pulse signal from the distance detection part 7 is radiated against the obstacle 4 through the transmission antenna 8. The ultrasonic wave reflected from the obstacle 4 is input to the receiving sensor 9, then it is differentiated by the ultrasonic wave receiving part 6, and a rise pulse is obtained. On the other hand, a rise synchronizing pulse is obtained at the distance detection part 7, from a pulse signal fed to the transmission part 5, an alarm signal is input to the alarm part 3 provided near a dashboard when the time difference between said pulse and a rise pulse which is an output from the receiving part 6 has exceeded the set point, then the alarm is send out. |
