REAL-TIME SPEECH CODING AND DECODING FOR GSM SYSTEM AND ITS IMPLEMENT IN VC

摘要

Speech signal is the most important part of the GSM mobile communication, thus the speech coding technology and high efficiency digital modulation technology can provide a higher system capacity for digital mobile networks than analog mobile network. Most of the implementation of speech code-decode is mainly in DSP platform, but this paper presents three low-rate speech coding schemes provided in the 3GPP protocol and the way to implement them in VC platform. We describe a compressed method to greatly reduce the size of the coded audio files. In addition, we can play decoded audio files in VC++ in real-time. It is impossible to play audio files in the DSP platform. So our method in VC platform is better than the method in DSP platform.