Optimization on Ultrasonic Time-of-Flight Measurement System Based on Self-Interference Driving Technology

Determination accuracy of ultrasonic time-of-flight can be easily affected by noises in practical measurements.Focusing on this problem,this paper combines with three advanced techniques to achieve the accurate time-of-flight measurement.Firstly,self-interference driving ultarsonic waves are stimulated from the piezoelectric transducer by amplitude and phase modulation techniques.Secondly,phase monitor is designed for roughly pre-detecting the received ultrasonic wave arrival time.Finally,double-threshold algorithm is employed for the final time-of-flight determination.The system is integrated in a single PCB board that is made up of digital signal processor,complex programmable logic device and some functional modules.Comparing with the traditional ultrasonic time-of-flight threshold crossing method,the systen has some advantages such as high resolution and high nosie suppression.