中文说明：该文件包含了一些常用的声辐射噪声的特征提取方法，包括波形的包络特征，高阶谱特征，分形维特征，奇异指数特征等。
English Description：
The file contains some common feature extraction methods of acoustic radiation noise, including envelope feature of waveform, high-order spectrum feature, fractal dimension feature, singular index feature, etc.