ULTRASONIC DISTANCE MEASURING APPARATUS

摘要

PURPOSE:To enable an accurate measurement of the height of a trolley line by measuring the distance to an object to be measured based on the propagation time of an ultrasonic wave from an ultrasonic wave transmitter provided on the top of a moving vehicle. CONSTITUTION:A modulated pulse wave is applied to a transmitter 5 with a transmission circuit 7 and transmitted to a trolley line 2 right thereabove therefrom 5. The ultrasonic waves reflected on the trolley line 2 reaches receivers 6 and receiving circuits 8 which transmit only those above a certain preset sound pressure to a signal processing circuit 9 as being accepted. By a synchronous signal (a) from the circuit 7, the circuit 9 starts to pick up the earliest one of the signals received from the receivers 6 and converts its propagation time of the ultrasonic waves into a current output, which is outputted as a signal proportional to the distance.