P-wave velocity is measured by through transmission using 500 kHz or 1 MHz (natural frequency) wafer-shaped crystals that are located on the back side (away from the specimen) of each end cap. A pulser sends an electrical signal, with a 400 volt pulse height, to the transmitting transducer. The received signal typically has a 200 kHz frequency and is amplified, digitized, displayed on a digital oscilloscope, and recorded by a computer. Acoustic compression-wave and shear-wave velocities, Vp and Vs, are calculated from the specimen length/measured travel time corrected for system delays.
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