Research On Data Transmission System Based On Analog Video Channel

Video technology can be divided into two categories named analog video and digital video technology according to signal type, with the rapid development of digital processing technology and microelectronic technology, the superiority of digital video technology in data transmission is going to emerge. While the cost-reducing, high reduction of analog television, making the analog video technology particularly impressive. However, digital TV to replace analog television has become a trend that will make the analog video channel appear idle, thus will result in a tremendous waste of channel resources. Teletext technology come into being because of various reasons, teletext technology transport digital data when the video channel is idle, thus greatly improving the efficiency of the transmission in analog video channel. The contents of this paper is realizes the transmission of digital data in analog video channel.Firstly, this paper describes three standard video signal, by comparing the performance characteristics and popularity, we can decided which standard to choose. Studying the synthesis process of the video signal from luminance signal and chromatic aberration signal, the transmission solution using the luminance component of video signals is proposed. Proposing three encoding schemes by referring to the Nyquist sampling theory and the limit of the transmission bandwidth at the transmitting end, including the data encoding scheme based on the level detection, the data encoding scheme based on edge detection and the ary amplitude modulation scheme, putting forward appropriate judgment solutions after analysis.Secondly, instructing the software design of sender and receiver.Introducing the development process of SOPC system briefly, including the embedded process of NIOSII processor and the addition of the macro function module. Introducing the design and function of each function module of transmitter and receiver in detail.Finally, presenting the construction process of the hardware circuit in detail, including memory chips, network chips, video chips and other peripheral circuits. Then sending and receiving data through the hardware platform which is finished, analyzing the source of the error by the experiments between sender and receiver, putting forward improved scheme and making board-level test, as a result, the bit error rate is less than 10^-4 when the data transfer rate is 2.88Mbit/s.