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

Adaptive Difference PCM code in matlab

已成功移植到51单片机上的ADPCM压缩、解压缩源代码，输入为14bit PCM信号，输出为4bit ADPCM信号。-51 single-chip has been successfully transplanted to the ADPCM compression, unzip the source code for the 14bit PCM input signal, the output for the 4bit ADPCM signal.