In the past 50 years, speech encoding technology has been made quite great progress. Up to now, the speech quality of encoding algorithm above 4 kbps is almost equal to that of PCM encoding algorithm. And it is being brought into the practical period.

• 语音编码技术在过去的50年中取得了长足的发展，到目前为止，4kb/s以上的编码算法在语音质量上已接近PCM波形编码的水平，并正在进入实用化阶段。