Research On Decision Feedback Equalizer For ATSC DTV Receivers

Technology of Digital Television (DTV) broadcasting is the third revolution in the technical history of TV broadcasting. Many countries have studied on it for a long time, and they had developed corresponding transmission systems respectively. Among these developed systems, terrestrial broadcasting is the most classic representation for its complexity. Presently, three terrestrial broadcasting standards have been set, e.g. 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 chip of ATSC DTV receiver.Firstly the author introduces digital terrestrial television technical background and present research situation around the world. Then the author introduces ATSC digital terrestrial transmission system and emphasizes the importance of equalizer in the receiver. Whereafter the author introduces the basic theory of equalizer. In order to combat with strong echo fading, this dissertation emphasizes to study coefficients updating algorithm, and proposes a dual mode blind equalization algorithm and a stop and go algorithm based on reliability information of viterbi decision device。Simulation proved the proposed algorithms farther improve the ability to combat with strong echo fading channel. In order to reduce implement complexity of decision feedback equalizer, this dissertation also proposes an improved coefficients updating way based on existing reduced-complexity tech, farther reduces implement complexity of decision feedback equalizer. In the end the author makes a summary and expectation of this dissertation.