论文部分内容阅读
本文对超声检测中常遇到的变采样问题进行讨论,比较了两种实现方法:基于特征值的二次采样和滤波器组,并给出了二次采样算法。通过试验,对这两种方法在超声信号变采样前后时频域特性的变化做了比较分析,得出前者可以很好地保留检测中所需的特征信号,但频域特性较差;而后者有很好的频域特性,便于进行时频分析。
In this paper, the variable sampling problems often encountered in ultrasonic testing are discussed. Two methods are compared: subsampling and filter banks based on eigenvalues, and the subsampling algorithm is given. Through the experiment, the changes of the time-frequency characteristics of these two methods before and after the change of the ultrasonic signal are compared and analyzed, the conclusion is drawn that the former can well preserve the characteristic signals required for the detection, but the latter has poor frequency domain characteristics; Have good frequency domain characteristics, easy for time-frequency analysis.