中文说明： 基于小波分析(用小波db4对信号进行多尺度分解7层），对脑电信号进行不同频带的分析，并绘制出功率谱。
English Description：
Based on wavelet analysis (using wavelet DB4 to decompose the signal into 7 layers), the EEG signals are analyzed in different frequency bands, and the power spectrum is drawn.