The wavelet coefficient of the feature band was regarded as the feature parameter of the Acousto Ultrasonic signal and it can distinguish defects from the adhesively bonded joints.
以此特征频带的小波变换系数作为声-超声信号特征参数，可分辨出胶接区域的缺陷信号。
2
The validity of this method is checked by both band structure calculations and transmission measurement of ultrasonic experiment.
通过对照带结构计算和超声实验测量，我们检验了这种计算方法的有效性。
3
Based on the characteristic of the Wide-beam ultrasonic flowmeter, automatic gain control amplifier and the tracking band-pass filter are devised.