Title :
A novel technique to measure the group velocity of sound in dispersive media
Author :
Zhao, Z. ; Adenwalla, S.D. ; Ketterson, J.B. ; Sarma, Bimal K.
Author_Institution :
Dept. of Phys. & Astron., Northwestern Univ., Evanston, IL, USA
Abstract :
A technique is proposed for measuring the group velocity of sound by a frequency-modulated (FM) continuous wave (CW) technique. Detailed calculations are presented, showing that V/sub g/=( delta omega /sub m// delta phi )d, where V/sub g/, delta omega /sub m/, delta phi , and d are, respectively, the group velocity, change of modulation frequency, phase change of the received signal detected by a biphase lock-in amplifier, and the distance traveled by the sound. The approach has the advantage of high resolution compared to the conventional time-of-flight measurement technique.<>
Keywords :
frequency modulation; ultrasonic velocity measurement; biphase lock-in amplifier; continuous wave; dispersive media; frequency-modulated; group velocity; phase change; resolution; sound; Amplifiers; Delta modulation; Frequency measurement; Frequency modulation; Phase detection; Phase frequency detector; Phase modulation; Signal detection; Signal resolution; Velocity measurement;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
