利用零相位数字滤波器检测EEG睡眠纺锤波

Detecting EEG Sleep Spindles by Digital Filtering with Zero Phase Error

脑电信号是极其复杂的非平稳信号。能否有效地辨识出EEG中所包含的各种成分或者得到判断某种病理特征所需要的成分 ,对于发挥EEG的最大作用具有重要的临床意义。系统的相移可以改变输入信号中各分量之间的相对相位关系 ,因此即使系统的增益对所有频率都为常数的情况下 ,也有可能在输入的时域特性上产生很大的变化。讨论了FRR与RRF数字滤波方法及其实现。利用该方法可以使系统具有零相位特性 ,实现脑电信号的零相位失真滤波。根据睡眠纺锤波的定义 ,利用零相位数字滤波器 ,直接在时域中检测睡眠纺锤波 ,得到了较好的检测结果。

EEG signal is a kind of very complex non stationary signal. It is of important clinical values for using EEG most efficiently to distinguish all kinds of components in EEG or getting needed components to judge some pathology features effectively. The phase moving of the system can change the relative phase relation between the components in the inputed signal, so there can be a great change of the feature in time domain of inputed signal. The FRR and RRF digital filtering methods and their realization are discussed. By using these methods, the system can be of the feature of zero phase error, and the filtering of EEG signals with zero phase error can be realized. Based on the definition of sleep spindles, we can detect sleep spindles in time domain directly by using digital filtering with zero phase error.