实现了adpcm到pcm的转换，单通道 8KHz采样-adpcm file convert to pcm file

The ADPCM package is a flexible simulation tool for an adaptive differential encoder and decoder with backward predictor adaptation. It uses an LP-based (Burg) adaptive predictor and a nonuniform quantizer with mu transfer function. It generates the

ADPCM编译码器，可以将语音信号转换为ADPCM码，并将其译码为原声音源。(ADPCM encoder and decoder)