Study On Arithmetic Of Carrier-Recovery For DMB-T System And Its FPGA Realization

Digital TV transmission technology for terrestrial which is transmitted by radio waves combined with full digital signal transmitted becomes one of the most high-tech concern field because of the support from the State Administration of CHN Radio & TV. Of course, the technological superiority is also another reason. As the system based on TDS-OFDM modulation method, however it is extremely sensitive to carrier frequency offset, this offset of DMB-T could damage to the orthogonality between carriers, and then the system performance will worsen enormously. This paper will focus on carrier recovery algorithm researches for DMB-T system, and carries on realization with FPGA, confirms the module design finally to make sure correctness and completeness.This study is based on "Research on Receiver Chip about DMB-T", the main work is as follows:1. Analysis the system principle in view of the characteristic of DMB-T system, The whole system is divided into some subsystem, such as front-end processing,Synchronous,equalization,FEC etc. Focus on the research of carrier recovery, the discussion of Costas and maximum likelihood method, after comparing two of them, the finally arithmetic is confirmed.2. FPGA Realization of Carrier Recovery. Because of the whole hardware system base on SOC, the asynchronous timer problem exist, so the different time-domain module should be distributed correctly when the whole system structure is measured off. Enter the synchronous Subsystem by top-down way, confirm the function need and hardware structure of carrier recovery module. Owing to the complicated control of state machine and a mass of data process module inside, it can lighten the data path, burden。When Submodule is design in detail, APB and Data transmission interface is design first, and then, the whole CRU control module and state machine control of AFC is implemented.At last, the data processing unit is designed. By using the analysis of timing requirement and logic structure, the finally design is given.3. FPGA verification scheme for carrier recovery module is designed, general verification scene and platform is builded to verify the project. Meanwhile, the simulation verification under the environment of NC-Verilog for the module is done, which follow the principle of interface to inside module, and the finally result is given, then make sure the function is realized correctly and completely.