说明： DPCM采用预测编码的方式传输信号，所谓预测编码就是根据过去的信号样值来预测下一个信号样值，并仅把预测值与现实样值的差值加以量化，编码后进行数字信号传输 (DPCM prediction encoding using transmitted signal, the so-called predictive coding is based on past signal sample values to predict a signal sample value, and only the predictive value and reality-like values to quantify the difference, the encoded digital signal transmission)
