Research On Equalizer Of ATSC Standard

Technology of Digital Television (DTV) broadcasting is the third revolution in the technology history of TV broadcasting. Integrated with the modern communication technology, many countries have done research in it for a long time, and they have developed corresponding transmission standard respectively. Among these developed systems, terrestrial broadcasting is the most typical representation for its complexity. Nowadays, three terrestrial broadcasting standards have been set, such as DVB-T (Europe) and ISDB-T (Japan) based on OFDM tech, ATSC (U.S.A) based on VSB tech. Among these standards, To remove seriously distorted channel fading is current focus. Equalizer is the main point to handle channel fading, so it holds the balance of performance in the whole receiver.This dissertation depends on the project of baseband decoded chip of ATSC DTV standard. Firstly the author introduce its technical background and present research situation, illustrate the basic structure of the VSB transmitter to emphasize the importance of equalizer. Then according to basic classification and structure of equalizer, analyze the equalization theory and two equalizer algorithm. In order to attain performance based on ATSC, study all kind of approach to improve the performance of VSB equalizer and its feasibility, particularly aim at strong echo fading near mainpath. A joint equalization structure which adopt decision feedback equalizer and maximum likelihood sequence estimate equalizer is proposed based on the decision feedback equalizer. The simulation result shows, when the structure has little effect on the performance of the long echo delay, it can obtain better performance than DFE alone.This Paper put up with a joint structure based on decision feedback equalizer which use channel estimator to track fast time-vary channel. A satisfactory result is obtained through analyze and verifiy in terms of emulation.