Research Of The Equalization Algorithm In ATSC System

With the development of digital television, more and more countries and regions have been change using of analog TV into digital TV because of the higher rates, clearer image. Digital television has gradually entry every household. However, there are three major current international standards of terrestrial digital TV DVB-T, ATSC, and DTMB. In order to meet more sophisticated customer demand for terrestrial digital television, we need to study a equalizer which could apply in multi-standard. Now, frequency domain equalizer has successfully implemented in two standard DTMB & DVBT, and achieved good results. However, under the ATSC standard, time domain equalizer has been dominated. So if the same piece of silicon integrated time domain, frequency domain equalizer is bound to lead circuit of waste. So we are working on a way to achieve the frequency domain equalizer receiver in ATSC standard. The research of the ATSC is mainly in developed countries such as Europe and the United States. The study of equalization in the ATSC receiver is always a hot and difficult part. Until now all current research on the ATSC equalizer is in the field of adaptive filter. The most common is the ATSC Standards Association recommended decision feedback equalizer (DFE), the other is the adaptive frequency domain equalization (FDAE).This paper analyzes the DFE and the FDAE equalizer structures and algorithms to analyze and compare the advantages and disadvantages by accessing to a large number of literatures on the frequency domain equalizer. Then we developed a equalizer for ATSC standard based on a time domain/frequency domain hybrid equalizer structure which add a noise predict part on the base of FDAE. It could not only avoid the high complexity of DFE, but also to make up for FDAE the convergence performance deficiencies. First of all, research the effectiveness of the hybrid equalizer structure for ATSC standard. Then we use matlab to set up the equalizer structure and simulation its performance. Using c code to embedded it into the existing ATSC receiver platform and simulation of system performance under various circumstances. Finally we get an optimization of the hybrid domain adaptive equalization (HDAE). The equalizer performance in the static channel conditions can replace decision feedback equalizer completely and have the low computation of FDAE. The lack of the dynamic channel performance is slightly worse than the decision feedback equalizer.Finally, according to HDAE equalizer convergence speed and dynamic performance of the shortcomings, we give a number of directions for improvement.