A novel technique to measure the group velocity of sound in dispersive media.
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(g)=(deltaomega(m)/deltaphi)d , where V(g), deltaomega(m), deltaphi, 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.
Zhao
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Z
Dept. of Phys. and Astron., Northwestern Univ., Evanston, IL.
Adenwalla
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SD
Ketterson
J B
JB
Sarma
B K
BK