中文说明：自相关虽然能够判断清/浊音，并估计浊音的基音周期，但是其运算量很大，用乘法运算所需时间较长。为了避免乘法，采用短时平均幅度差函数（AMDF），验证AMDF与自相关有类似的作用，即平均幅度差函数能够代替自相关函数进行语音分析。
English Description：
Although autocorrelation can judge voiced / unvoiced sounds and estimate the pitch period of voiced sounds, it has a large amount of computation and takes a long time to multiply. In order to avoid multiplication, the short-term average amplitude difference function (AMDF) is used to verify that AMDF has similar effect with autocorrelation, that is, AMDF can replace autocorrelation function for speech analysis.