本文利用“等时区方法”确定出二阶离散系统最速控制综合函数，井依此构造出离散形式的跟踪一微分器．数值仿真表明，这种跟踪一微分器跟踪输入信号既快速、无超调,又无颤振，且能给出较好的微分信号．

In this paper, the synthetic function for the time optimal control of the second-order discretetime system is obtained by the Isochronic Region method. Based on this function, the discrete form of tracking-differentiator is constructed. Numerical simulation shows that this discrete form of tracking-differentiator can quickly trck an input signal without overshoot and chattering and can produce a good differential signal.