But , the eeg signal that we can acquired is very weak and is badly contaminated by strong background noise , such as electrooculogram ( eog ) , electrocardiogram ( ecg ) , and line noise ( 50hz or 60 hz power frequency interference ) , etc . eeg is a typical non - stationary random signal with a certain extent of non - gaussian and non - linear character 但是我们能够获得的脑电信号一般非常微弱、并伴有很强的背景噪声，是一类典型的非平稳的随机信号，且存在一定的非高斯性和非线性。传统的分析处理方法一般将脑电信号近似认为是线性的准平稳的高斯分布随机信号，这使得分析结果往往不能令人满意、实用性差。
