用于减小定时抖动的数字预滤波器设计

推导了一种用于减少定时抖动数字预滤波器的冲激响应表达式，提出了一种数字预滤波器的设计方法，设计了一种优化数字预滤波器。通过对定时恢复环的仿真，讨论了环路的收敛情况，比较了所设计的数字预滤波器和无预滤波器时环路定时抖动与信噪比、定时抖动与环路噪声带宽、误码率与信噪比的数量关系，证实所设计的数字预滤波器对减少定时抖动非常有效。
关 键 词 定时抖动; 预滤波器; 定时恢复; 优化设计; 数字滤波器

Abstract An expression of impulse response was deduced and a kind of optimum design method for digital prefilter is proposed in this paper. Design a kind of optimum digital prefilter. Simulate a timing recovery loop in order to get statistical data about timing jitter. Discuss the convergence characteristic of timing recovery loop. Compare the relation between timing jitter and signal to noise ratio, the relation between timing jitter and noise bandwidth of loop, the relation between symbol error ratio and signal to noise ratio in optimum prefilter and no prefilter. The result of simulation proved this design method has great affection to reduced timing jitter.
Key words timing jitter; prefilter; timing recovery; optimize design; digital filter