搜索

x
中国物理学会期刊

控制超声测量用换能器首次波幅度比的方案

CSTR: 32037.14.aps.30.91

A SCHEME TO CONTROL THE FIRST-SECOND CYCLE AMPLITUDE RATIO OF TRANSDUCERS FOR ULTRASONIC MEASUREMENTS

CSTR: 32037.14.aps.30.91
PDF
导出引用
  • 超声可用于测量一些非声学特性。在这些应用中,需要准确测量超声波的渡越时间。为此,不应漏测接收信号到达时的前一两个波,这要求首波的幅度等于或大于次波的幅度。本文分析了发射和接收换能器的瞬态特性,包括双探头的和单探头的,从而证明,如果增加换能器背衬的声阻率,首次波幅度比可以从小于1加大到1或大于1。这是对轻负载讲的。如果负载相当重,首次波幅度比自动地比较大。

     

    In the ultrasonic applications of measuring non-acoustic characteristics, it is impor-tant that the time of flight of the ultrasound be measured with accuracy. One significant step to achieve this is to ensure that the first few cycles of the received ultrasonic signal should not be missed. This in turns asks for the amplitude of the first cycle being as large as, or greater than, that of the second. By studying the transient responses of the transmitting and receiving transducers, either separated or two united in one, it is shown that the first second cycle amplitude ratio can be increased from less than one to one or more of the specific acoustic resistance of the transducer backing is enhanced to a suf-ficiently high value, but not necessarily as high as the specific acoustic resistance of the piezoelectric plate. This holds for the case of light loading. For the case of heavy load-ing, the amplitude ratio is found to be inherently large.

     

    目录

    /

    返回文章
    返回