The Research And The Simulation Of DVB-T System

DTTB (Digital Television Terrestrial Broadcasting) is one of the present digital television broadcasting modes, whose transmission media is earth. After a decade of intense research and development, the standards of Digital Television satellite Broadcasting and Digital Television cable Broadcasting have been confirmed. But the standard of Digital Television Terrestrial Broadcasting is still in disputation, for its transmission environment is rather awful, its spectrum resource is very limited and its service required is disperse, so it is potential to be improved in many aspects.DVB-T (Digital Video Broadcasting) specification is one of the DTTB standards. It has better results in digital television program terrestrial reception test and has good appraisement in digital television broadcasting industry. This thesis based on Europe DVB-T COFDM (coded orthogonal frequency division multiplexing) system, does a lot of research from the development, the technique instrument of DTTB to the whole DVB-T system structure and system flow. Then brings forward its own ideas and optimizing advices after the stimulation of normal DVB-T system.Firstly the thesis describes the needed conditions, the technical difficulties and the present problems of DTTB. And pays emphasis on analyzing the system structure and system flow, the core techniques, the channel characteristic and parameters of DVB-T system. The system adopts some core techniques such as COFDM, a lot of TPS (Transmission Parameter Signalling) insert and guard interval, and so on. So it can withstand high-level (up to OdB), long delay static and dynamic multipath distortion. The system can synchronously transmit digital television program and analog program, and it possesses unique advantage on mobile reception. At the same time , DVB-T system needs to be improved on the immunity against gauss white noise and the mode of channel coding. In order towell know the realization of system flow and the capability of system, then with the software-System View, and using the relevant icon function in SystemView's DVB library, the thesis simulated the whole DVB-T system. The simulation carries through on three aspects as the ideal system, the disturbed systems with multipart! distortion and gauss white noise distortion. The simulation of ideal system aims at absolutely clean channel, and the nonideal systems respectively set their channels as Ricean channel (multipath distortion channel) and AWGN (gauss white noise distortion channel) .At the end of simulation, it use examining means of communication system as BER(bit error rate) analysis and eye diagrams analysis, then gives a summarize and a comment to the system.