Design Of Speech System For VoIP

As the science and technology developing recently, it is true that speech disposition already interact with people's daily life. With the digital and network of speech signal, VoIP is coming in our world. VoIP (Voice over IP) is a fast developing technology of voice communication. In VoIP system, voice communication is transmitting by Internet but not traditional telephone line. By VoIP , the real-time voice communication is possible between computer and computer, or between common telephone and common telephone, or between computer and common telephone. The transmission wideband of traditional telephone net is 64k/s, but VoIP can transmit with TCP/IP protocol, when it based on IP network, compress and pack the analog voice signal.This thesis makes an investigation for relational research situation of home and international first, and then introduces the basic transmission and advantage of VoIP. After that this thesis gives out the software and hardware design of speech disposition system. This thesis also explains the each module and its relational knowledge of the design.With the aim of increasing the real-time responding ability and signal processing ability, after introduce DSP detailed, thesis use TMS320VC5402 as the hardware core of all the system. Which both produced by TI corporation, TLC274 and TLC320AD50C are used to gather or enhance and A/D transformation of the voice signal. The network part uses a common chip, RTL8019AS. This thesis explains detailed the connection of TLC320AD50C and RTL8019AS with TMS320VC5402.After comparing with mainly voice algorithm, this thesis chooses G.729A finally. And this thesis choose LWIP after the introducing TCP/IP protocol. At last, through the analyzing and explaining for embedded RTOS, this thesis chooses uC/OS-II as the core of software in this thesis.In this thesis, the process of speech disposition is that: firstly, analog speech signal is collected and A/D transformed by TLC320AD50C;secondly, digital speech signal is compressed by TMS320VC5402 based on G.729A speech compressing code;thirdly, the code of speech signal is transmitted by RTL8019AS to the Ethernet. All the process is administered by uC/OS-II.