| 摘要 |
<p>PURPOSE:To judge obstacles on a road in the range from a low speed to a high speed effectively based on reflected waves by providing a vehicle-speed detecting means, two timing-command means, an ultrasonic-wave-signal generating and receiving means, a judging-signal generating means, a comparing means and the like. CONSTITUTION:A timing-command means 1 supplies an ultrasonic-wave-pulse command signal V0 to an ultrasonic-wave-signal generating means 3 for a specified time at every specified interval based on the vehicle speed pulse signal from a vehicle-speed detecting means 9. The means 2 drives an ultrasonic-wave transmitting means 3 with a driving signal V1. The means 3 projects the ultrasonic pulses on a road surface (a) at the slant forward part. An ultrasonic-wave receiving means 4 receives a reflected wave V2 from the road surface. A received-signal processing means 5 amplifies the signal V2 and performs AM detection. An AM detected signal V30 is outputted into a comparing circuit 8. A second timing command means 6 operates a judging-signal generating means 7 with the signal V0 as a trigger. The signals V30 from the means 5 is compared with judging signals V5 and V6 from the means 7 in the comparing circuit 8, and a detected signal V7 is outputted.</p> |
