研究了高清晰度数字电视（HDTV）中的频率同步及采样钟同步技术对其中的小数倍频偏和采样钟偏移估计做了算法仿真分析，结合实际工程应用提出一种适用于数字视频地面广播（DVB-T）编码的正交频分复用（COFDM）调制系统的小数倍细频偏和采样钟偏移联合估计算法并提出了相应的现场可编程门阵列（FPGA）实现方案，设计出的硬件电路经国家高清电视总体组（TEEG）的HDTV功能样机调试证明了该算法的易实现性和优良性能。

Timing jitter, frequency offset, carrier phase jitter and sampling clock frequency offset are the main synchronization errors encountered by OFDM systems. As many literatures have proved, OFDM systems are very sensitive to frequency errors. In this paper, three new methods to estimate the integer part of frequency offset are proposed, simulation results show its robustness to mitigate the multi-path effect and its enlarged estimation range for frequency offset. The correspondent Field Programmable Gate Array (FPGA) circuit through test in HDTV prototype in Team of Engineering Expert Group (TEEG) proves its feasibility and availability. The proposed method is also suitable for burst mode transmission systems such as Wireless Local Area Network (WLAN) and Fixed-Broadband Wireless Access (F-BWA).

There have been many papers concerning about the Peak to Average Power Ratio (PAPR) reduction and High Power Amplifier (HPA) linearization techniques for wireless OFDM communication systems. Few papers, however, make deep analysis on the relation between these two techniques. Based on Saleh’s memoryless Traveling Wave Tube Amplifier (TWTA) model, computer simulations and analysis in this paper demonstrates that, especially when the HPA is working near or in the saturation region, a predistorter will cease to be in effect. In such cases, PAPR reduction techniques may be resorted to help to improve the Adjacent Channel Interference (ACI), BER performances and HPA efficiency 1.

Timing jitter, frequency offset, carrier phase jitter and sampling clock frequency offset are the main synchronization errors encountered by OFDM systems. As many literatures have proved, OFDM systems are very sensitive to frequency errors. In this paper, an improved method to do decimal frequency offset estimation in time domain is proposed. In addition, lots of simulations have proved that when the decimal frequency offset in data streams approaches to 0.5 of the subcarrier spacing, a wrong estimated frequency offset with inverse polarity will be presented, therefore, a novel adjusting model to deal with this problem is also proposed in this paper. Simulation results show that the mean square error (MSE) can be significantly improved by over three order of magnitude at high SNR with the proposed method compared with the conventional method [1], [2]. The correspondent Field Programmable Gate Array (FPGA) circuit through test in HDTV prototype in Team of Engineering Expert Group (TEEG) proves its feasibility and availability.

通过对欧洲OFDM接收方案的分析，提出了一种易于FPGA实现的同步解决方案。结合计算机仿真和工程实现，提出了一种新的符号定时同步算法。该法克服了常规ML方法估计出的符号同步位置波动较大的缺点，弥补了门限估计方法中实际同步起始位置与估计位置相差大的不足，可以较好地实现符号定时同步。