信号特征提取16个时域、频域指标 均值、标准差、方差、 偏斜度指标、峭度指标、 峰-峰值、峰值、均方幅值、平均幅值、方根幅值、波形指标、峰值指标-Signal feature extraction 16 time domain, frequency domain mean, standard deviation, variance, skewness index, kurtosis index, peak- peak, mean square amplitude, average ampli