The Research Of The Speech Compressing Coding G.723.1 Standard

With the rapid development of satellite communications, digital mobile communications and personal communications, the conflict between user's demand and capability of communication channels is more and more outstanding. How to improve the usage efficiency of resources available is the focus to which people have put much attention. Now, the standards of speech compression coding provide a way of transporting speech signals efficiently. In fact, all of them are to reduce the baud rate of data under definite speech quality.G723 aerithemetic is a compressing arithemetic that proposed by ITU-T and applied in speech and other audio frequency signals of low velocity multimedia services,such as:H.323,H.324 system.This arithemetic provides inspection to silence speech frames and fills in comfortable noise when it is silence.If optimize system and increase the complexity limitedly,we can get higher quality of speech.G723.1 is also available in music or other voice signals,but the managing effect is not as good as speech's.Among the standards which are established using mixed coding technology, G723.1 has the highest efficiency, and is widely used in many fields. But, to gain the high quality and low baud rate, G723.1 pays out the costs, such as the high complex of coding arithmetic, high delay and large store space. Each of them brings up the difficulties of its real-time implementation. The first step of use the arithmetic is to understand it accurately and code,then change it into program can be run, this is the precondition, but we can't assure that the capability can meet the demand of customers, so we shoud improve the arithmetic according to the demand of practice. At the same time, in practice, the program also limited by the hardware such as:size of memory,speed of CPU,etc.Detailed the basic technology of speech coding and based on the in-depth study of G723.1, the paper implements it using C language and provides some optimizing policies with respect to code-book research. At the same time, based on the analysis of TMS320C5410 EVM environment, the paper gives system design, hardware design and the flow of software design.