Application of Digital Techniques in Ultrasonic Sensors

摘要

Digital techniques for the measurement of the time of flight, including the time-frequency signal analysis techniques and the cross-correlation algorithm are presented. The proposed methodology employs a suitable time-frequency to represent (using short time fourier transform.) and extract the envelope of the reflected pulse, together with a suitable pulse detection algorithm (the cross-correlation method ) for the estimation of time of flight. The systematic and random components of uncertainty in ToF measurement are analyzed using these techniques. These techniques are shown to provide high resolution measurements, and good noise rejection performance, to make a fully digital measurement possible.