Digital Television Ground Transmission System Based On Dvb -t Originated The Fpga Implementation

Digital television is one of the product of digital information technology. It put the way of television transmission and the information technology collection in a body, and can interactive with users. As one of the most complicated technology of the developing digital video broadcasting, digital terrestrial video broadcasting can be used in many kinds of scenarios including wireless and mobile environments. Among the several standards for Digital Multimedia Terrestrial Broadcasting, the European Diginal Video Broadcasting-Terrestrial(DVB-T) has been proved excellent in many aspects such as fix, mobile and portable receiving, and so on. DVB-T uses COFDM modulation system, which decreases the inter symbol interference caused by dynamic multi-path and Doppler shift. And the setting of space protection reduces the impact of multi-path on the carrier orthogonality. All makes it easy for DVB-T to support mobile receiving perfectly.Focusing on the channel transmission system of Digital Multimedia Terrestrial Broadcasting, this dissertation studies the realization process of the transmitter of DVB-T system which has been widely used. Centering on the coding and modulation engineering realization based on DVB-T launching system, the dissertation has done main works as follows:1. Compared and analyzed the standards for Digital Multimedia Terrestrial Broadcasting which have been spread and applied maturely. On the base of the block diagram of transmitter system of DVB-T standard, the whole processing procedure of information codes is analyzed briefly.2. Analyzed the channel coding and modulation technology which are involved in the transmission system, illustrated the architecture process and the core technology of the DVB-T system. Combining the data flowing feature in DVB-T standard, introduced the regulations of the frame structure formation of OFDM symbol and the insertion of guard interval. 3. Implemented the algorithms by using FPGA including randomization for energy dispersal, outer coding(Reed-Solomon code),out interleaving(convolutional interleaving of12in depth), inner coding (convolutional codes with four code rates) and inner interleaving(Bit-wise interleaving and Symbol interleaver), signal constellations and mapping, frame formation and OFDM modulation. Using parallel implementation structure to achieve randomization for energy and a double port RAM to finish the convolution interleaving and symbol interleaver, which decreased the designing complexity and memory space.4. Set up a FPGA testing platform for DVB-T coding and modulation system. Several key modules have been tested on the circuit board and the frequency spectrum of modulated signal have been analyzed with the aim of verifying the correctness of the design.