Abstract
Global economic activity today demands that national measurement standards guaranteeing a high degree of accuracy in measurement be maintained, and that such ultrasonic field measurement standards as ultrasonic power or ultrasonic pressure be included. Ultrasonic power standards and hydrophone sensitivity standards covering conventional medical ultrasound fields have been established in most of the advanced nations. The Consultative Committee for Acoustics, Ultrasound and Vibration (CCAUV) was established in 1998 under the Metre Convention. Only recently, however, have ultrasonic standards been established, and end-users of ultrasound measurement equipment do not appear to have yet acquired sufficient understanding of the metrology for ultrasound. In this paper I describe some historical situations of the metrology for ultrasonic measurement, the role of measurement standards based on the Metre Convention, and the present situation of ultrasonic standards established by the National Metrology Institute of Japan (NMIJ). Ultrasonic standards must apply to an expanded frequency range, and standards for high-intensity ultrasound will be essential. Issues of world-wide concern are increasing discussed at International Electrotechnical Commission (IEC), the Metre Convention, and similar gatherings. To contribute to this trend, I also discuss areas for further study that will enable us to reach the next level of ultrasonic standards at NMIJ.
