Realization Of Very Low Rate Speech Communication

With the development of information society and information technology, frequency is becoming more and more important. So we always in search of compression digital speech communication or low rate voice frequency grade channel. Digital speech coding plays an important role for this.More and more digital processing system has to be real-time mode or to be on-line mode. The requirement of hardware environment is higher and higher, especially in the design of embed system. The speech-processing arithmetic is more and more complicated, and ability not equal to our ambition that to deal with speech-signal real time with common processor. Special speech-chip can resole the problem of parallel and speed of speech-signal processing, so the application on the speech-signal processing system is especially important.At this point, this thesis emulated and simulated the core algorithm of low rate speech, with the purpose of high-performance low-rate special speech-chip. The main achievements of this work are summarized as follows:1. Do researches on the current situation of low rate speech communication, analysis the market prospect of low rate special speech-chip.2. The thesis realized the circuit design and debugging of AMBE2000, and finished 1.2kbps rate speech communication through hardware level, we got very good voice result.3. Finished encoding and decoding of LPC, the system is designed based on MATLAB, and the experimental results showed that the speech quality is very good even at the low rate 1.2kbps.4. For better rate and performance, the thesis also do a in-depth analysis and research on AMBE algorithm, finished the decoding simulation and verification.In conclusion, the studies not only have important theoretical meaning and great value to hardware realization of speech communication, but also make a good technological foundation for special speech-chip.