小波变换用于二次微分交流示波计时电位信号中有用信息的提取

Application of Wavelet Transform in Retrieval of Useful Information from d^2E/dt^2 -t Signal

小波分析是８０年代发展起来的一种新的数学分支。由于小波变换具有许多其它的 信号处理手段所不具备的优良特性，如正交性、可变的时－频分辨率和可调节的局部支持等， 使它成为信号处理的一种强有力的工具。作者将小波变换用于从二次微分交流示波计时电 位信号中提取有用的信息。研究了小彼变换次数、小波函数的种类、白噪音等因素对变换结果 的影响。实验结果表明：小波变换具有变换速度快，准确度高，易于从含有噪音和背景的示波 信号中提取有用信息等特点。

Because of the fine properties of orthogonality, orientation, flexible time- frequency windows and governed localized support, the wavelet transform in recovering useful information from second order differential osillographic chronopotentiometric signal (d2E/dt2-t signal) is investigated. Effects of the transform frequency, white noise and kinds of wavelet functions and the oscillographic signal on the transform results are discussed. In above- mentioned factors, the noise and transform frequency are two main influencing factors. Experimental results for the former influence indicated that for the noise and favorable peak shape a signal-to-noise ratio of 3 can be tolerated at the 5% error level, which means that a significant reduction in the detection limit can be obtained in comparison with the classical signal processing methods. And the findings for the latter showed that the peak height caused by depolarizer depends on decomposition frequency for the signal, and three transforms results in the best peak shape and the largest peak height. Thus, as compared with Fourier transform, using wavelet transform is easy to recover useful information from the osillographic signal contaminated by noise and background signal.