基于FFT的信号分解方法及其工程应用

Signal Decomposition Method based on FFT and Its Application to Ocean Engineering

提出了一种应用于处理平稳或者非平稳随机过程的信号分解、分析方法。该方法基于快速傅里叶变换(FFT)和带通滤波原理,通过限定固有模态函数的最大特征频带,将复杂信号序列按顺序分解为有限个固有模态函数。与现有方法相比,该方法分解得到的固有模态函数接近实际工程的单组份要求,最大特征频带的限定保证了固有模态函数分量真正意义上两两正交和信号混掺现象。借助于新的信号分解分析方法和对应的瞬态振动能量谱,揭示了在海洋工程领域的一些特殊现象。

A signal decomposition and analysis method applying to deal with stationary or non stationary random processes has been newly developed. One key innovation of this method concerns the endeavor to de- compose any complicated composite signal into signal components, based on the principles of fast Fourier transform and band-pass filtering. Another one concerns the introduction of maximum intrinsic band-width to define intrinsic mode functions. Comparing to available decomposition methods, it has been found that the de- composed intrinsic mode function due to this method satisfy the requirement of mono-component, and the in- troduction of maximum intrinsic band-width assures the pairwise orthogonality and aliasing phenomena of sig- nal components. By means of the newly developed signal decomposition method and the relating instantaneousvibration power spectra, many special phenomena relating ocean engineering have been found.