Effects of Pulse Distortion on Phase Velocity Measurements Using the Zero-Crossing Shift Technique
Thompson, R. Bruce
One of the technique that is often used in the measurement of phase velocities of guided elastic modes is the zero-crossing shift technique. Using this technique, one measures time delays (usually through a counter) of a specific zero-crossing for a number of different separation distances of two transducers. The phase velocity Vp is computed as the slope of the distance-delay plot. For non-dispersive waves, this produces no problem as the pulse retains its shape as it propagates.