| 摘要 |
<P>PROBLEM TO BE SOLVED: To easily and exactly measure a pipe diameter, using an acoustic sensor. <P>SOLUTION: An electric acoustic converter for an output and an electric acoustic converter for an input are arranged in a pipe, a sound wave having a fixed energy and/or power level(s) is output from the electric acoustic converter for the output to input the output sound wave into the electric acoustic converter for the input, and the pipe diameter is found by collating a value/values of energy and/or power level(s) of the input sound wave, a value of time constitution of an impulse response shape, values of the whole band level of a frequency transmission characteristic, a specified band level thereof and a specified frequency-weighed level therein, or a value/values of a peak and/or dip frequency/frequencies of the frequency transmission characteristic with a value found preliminarily. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
