自发自收超声信号源的设计

he ultrasonic signal is generated and received by the ultrasonic signal transducer and common accomplished. The system spontaneously is the realization of the resumption ultrasonic signal source. The design with EPM7128SLC84-15-CPLD of Altera company to controlling the core produce the 40 KHz square wave, after voltage amplification, driving ultrasonic transducer work. After reflection of ultrasonic signals from the receiver to receive, through the return of this voltage amplification CPLD, corresponding to the trigger signal microcontroller, SCM then pass numerical terms from SCM further processing. The system uses CPLD ultrasonic propagation time of capture, time information transmitted to the microprocessor. The accuracy depends on the CPLD count frequency measurement with high accuracy, low cost, real-time continuous measurement, the advantages of easy operation, the accuracy of measuring the accuracy of a theory1/12μs. for the future achievement of certain specific functions to lay a good foundation.