Design Of Digital Optical Terminal

With the development of communication technology, it is a crucial problem that how to transmit data correctly under so complicate electromagnetic environment. Compared with cable transmission fiber transmission has the strongpoint of electromagnetic interference proof and is slight .So it is adopted avidly as transmission channel.Combining digital technology with optical fiber transmission, this thesis presents a solution of uncompressed multichannel digital optical fiber transmission system. Based on time-division multiplexing and the serial digital data transmission technology, the proposed system can transmit standard video signal, audio signal and data signal over a single optical fiber. Also,In this solution, the design of the hardware and the programme of FPGA is taken as the major means of thesis.In the hardware sections, it contains: the filter designed for video, The technologies of analog-to-digital conversion, digital-to-analog conversion, parallel-to-serial conversion, serial-to-parallel conversion, audio sampling, PCM encoding and optical fiber transmission. As of hardware design, integrated methods of combining FPGA with ASIC, four layers of PCB and difference AC-coupled high speed data interface are applied to make this system be characteristic of high integrated quality, reliability and agility.In the thesis, the programme of FPGA is totally realized in both code and schematic diagram using Verilog language. It has completed the simulation, synthesis, implementation and configuration of every programme function by using Quartus II 5.1 software.This optical transmitter makes it possible for the real-time and synchronous transmission of multi-signals without distortion and at high quality. The module structure makes it flexible for further update. It is automatically compatible with PAL, and NTSC video standards. All its optical and electrical interfaces agree with the international standards and can work in different environments.Experiments show that the system works stably and It is a novel effective and practical scheme for security and surveillance systems.