Inst. of Acoust., Tongji Univ., Shanghai, People's Republic of China
George S. K. Wong
Inst. for Natl. Measurement Stds., Natl. Res. Council, Ottawa, ON K1A 0R6, Canada
Sound velocities in pure water at various temperatures were measured. A PZT transducer sends a 2-MHz pulse towards a target stationed at an accurately known distance of 120 mm away. The transit time between the forward pulse and the reflected pulse was measured precisely with statistical averaging and a reference timebase derived from the NRC cesium frequency standard. The transducer-target probe and liquid chamber was immersed in a temperature controlled bath that was under the control of a computer. Measurements were repeated with known concentrations of alcohol and distilled water. Uncertainties of the measurements will be discussed. The authors would like to thank Lu-Jie of the Tongji University for his contribution to the construction of the measurement circuits.