The Research And Implementation On Timing Recovery Of Digital Television Terrestrial Brocasting System

Digital Television is going to be widely used recently. DTV transmission is a kind of wideband and high data rate transmission, so the development of its theory and implementation will impel the development of next generation wireless communication technology. Therefore the research work of digital television terrestrial broadcasting system is important for industrialization of it.The channel conditions of real transmission systems such as DTV terrestrial transmission system are usually very coarse, so the receiver is the most important. Above all synchronization should be considered first, because synchronization is the foundation of receiver. The other parts in the receiver such as equalization and channel decoding cannot work without reliable synchronization. Under the background of the Chinese standard of DTV terrestrial broadcasting, this paper focus on timing synchronization, and then finish FPGA complementation process of timing recovery using PN. The paper introduces the development of digital television and gives the frame structure and modulation mode of the common systems, emphasizing the key effect of timing synchronization; and then introduces the basic structure of the digital receiver, summarizes the main method of timing synchronization, analyses the effect of timing offset, does some research about the theory of Farrow structure and the timing recovery loop.This paper has two contributions: one is giving a method of inducing Farrow coefficients by using Taylor formula, which is less complicated. Using a general time-sequence-based timing simulator, we prove the good performance of the coefficients; the other is developing a timing recovery scheme, which is suitable for common frame structure such as PN420 mode and PN595 mode. The scheme has been proved well by system simulation and performance analysis. It can adaptively use suitable frequency and phase detection method according to different channel models. The receiver works well in poor fading multi-path environments.