Conference Television Voice Terminal System Design

The video conference is a kind of multimedia communication system which will become a hot topic in the multimedia communication area in the 21st century. The video conference is the outcome of several techniques integrating together such as the computer, the communication network and the microelectronic. It require the information of different media be converted into digital form, be transmitted in various network in no delay and be good at communicating with others efficiently. Recently, with the rapid development of the high-speed IP network and internet and different digital data net(DDN), ISDN and ATM being built and coming into operation, the video conference' use and development enter a new age. At the same time, it will be more and more welcomed by the client.The video conference system is composed of the terminal, the transmitting channel and MCU(Multipoint control unit). In this paper, its critical techniques and development be chiefly introduced first. And then the emphases is laid on the techniques and the design related to the audio terminal.The audio terminal can be divided into two parts, namely the data transmitting end and the remote-control unit. The data transmitting end mainly samples and transmits the voice signal. The remote-control unit has four functions as follow. (1) control the operation mode of the data transmitting end and receive the digital voice signal from it; (2) process the voice signal with the AEC(audio echo cancellation) arithmetic; (3) compress the voice signal according to G.711 and G.722 standard; (4) After the voice signal is processed with other digital signal including image information, data information and control information in the multiplexer, the information is transmitted to the MCU. The main techniques and the design method related to each part is introduced in the paper.