动态多径信道DTMB频偏估计算法

Frequency offset estimation for DTMB in dynamic multi-path channel

针对在动态多径信道条件下残余频偏波动较大、难以获得高估计精度及大估计范围的问题,提出一种应用于数字电视地面多媒体广播(DTMB)系统频偏估计的改进算法.根据DTMB标准中相位旋转的初始相位规律,尽可能使参与相关运算的2段伪噪声序列数据一样,从而使系统可较容易地选出多条径参与偏频的计算,达到频偏估计的多径合成效果.多径信道下的仿真结果证明:该算法提高了动态载波恢复模块的工作稳定性,延长了系统锁定时间,系统残余频偏绕中心±10Hz以内波动,改善了系统频偏估计性能.

For the low performance of frequency offset estimation module in the dynamic multi-path channel and the difficulty of improving the estimation accuracy and broadening the scope of frequency offset estimation, an algorithm of frequency offset estimation in digital television terrestrial multimedia broadcasting （DTMB） system was proposed. The main research work was the discovery of the rules of preliminary phase of frame head in phase shift mode utilizing the rules to optimize the fluctuation of frequency offset in dynamic multi-path channel. Computer simulation illustrates the superior performance of the proposed algorithm in the estimation accuracy and the stability of remaining frequency offset. The remaining frequency offset fluctuates within ±10 Hz in high-doppler multi-path channel, thus improve the frequency offset estimation performance in the DTMB system.