The Research Of Speech Compression And Narrowband Data Communication Technology Based On DSP

Nowadays, communication should supply all kinds of good ways to satisfy people's need in exchanging information conveniently. Because most people transfer information by speech, which is the most important, efficient and convenient way in communication, speech communication holds the importance in modern digital communication system. However the sources in communication especially the frequency source become more and more valuable with the development of information society. Then more and more speech compress coding technologies come into being to decrease bit rate in transmission and data storage quantity when in memory. High speed DSPs (Digital signal processors) make it possible to realize the real real-time speech coding system. Besides, Mobile communication technology has been developing fast during the past years, and is infiltrating into people's life deeper and deeper. At the same time, interphone system is also developing quickly with mobile communication technology, and has been used widely in many fields like public security and traffic. After many years rapidly development of speech compression technology and interphone system based on it, they become more and more important.This paper firstly introduce an algorithm of low bit rate speech coding-MBE. So it can get more precise parameters of speech to improve the quality and robustness of speech in decoding part and the complexity of the algorithm is not increase apparently. We amended the pitch smooth algorithm in pitch first estimation phase, improved the estimating precision of speech pitch and the judgment voiced and unvoiced speech. Based on low rate bit speech coding, the paper analyses and emulators several ways of realization of narrowband data communication.At last, paper will present the design of low bit rate speech coding real-time system based on TMS320C6416DSP of TI Company. The system include CCS IDE software and other DSP's hardware peripherals including: AD /DA module-TLV320AIC23, CPLD, SDRAM and Flash. Besides, because of the need of the real-time schedule of tasks, the paper also introduce the transplant ofμC/OS-II on DSK6416.