數位地面視訊廣播系統(Digital Video Broadcasting-Terrestrial，DVB-T)是採用編碼正交分頻多工(Coded Orthogonal Frequency Division Multiplexing，COFDM)技術的通訊系統，而正交分頻多工系統具有高傳輸速率的優點，但因為使用多載波傳輸，當有載波頻率干擾時，會造成載波間干擾，造成系統效能變差。 本論文將以數位地面視訊廣播為研究系統，探討DVB-T同步方面的問題。所探討的問題包括有載波頻率及符元時序，將會說明這兩個問題的解決方式，並且使用Matlab模擬在多路徑通道及嚴重雜訊的環境底下之效能及特性。最終將對所說明的方法做整合，提出一個完整的架構，並以VHDL設計同步的模組電路。 COFDM (Coded Orthogonal Frequency Division Multiplexing) is used as the modulation method for the DVB-T (Digital Video Broadcasting-Terrestrial) system. The OFDM system has the ability to support high transmission data rate. Since the OFDM system is sensitive to carrier frequency offset and symbol timing error, how to make the synchronization perform well is an important issue. In this paper, we study the synchronization problems which include carrier frequency offset and symbol timing offset in the DVB-T system. Then, we construct a solution for synchronization in the multi-path and heavy noise environment. Matlab simulations are used to explore the characteristics and efficiency of the solution we proposed. Finally, we design the synchronization modules by VHDL.
