顾名思义，“小波”就是小区域、长度有限、均值为0的波形。所谓“小”是指它具有衰减性；而称之为“波”则是指它的波动性，其振幅正负相间的震荡形式。-As the name implies, " wavelet"　is a small region of finite length zero mean waveform. The so-called " small"　means that it has a decay　while the " wave"　refers to its volatility, the amplitude of alternating positive and negative shocks form.