| 摘要 |
The circuit includes an ultrasonic wave transmitter (10) having a decoder and a driver (12,13) for generating ultrasonic signal having frequency of 40 KHz and providing 40 KHz signal to a transducer, a receiuer (20) having a receiving transducer, a multiplexer (21) for multiplexing reflected ultrasonic wave, a filter, and a signal modulator (24) for transmitting reflected signal to a system controller (30), a system controller (30) for supplying 3-bit control signal to the decoder (11) and multiplexer and for calculating a distance from an object by a reflected signal. |
