对输入的一有理Z变换表达式（输入分子和分母系数序列），分别画出：

（1）零极点图

（2）z在单位圆上时z变换所对应的DTFT的幅度谱和相位谱

（3）逆z变换所得序列，在各种不同的收敛域下（包括了右边序列，左边序列和双边序列的情况）

-the importation of a rational expression Z-transform (input coefficient of the numerator and the denominator sequence), respectively paint : (1) The pole-zero plan (2) z in the unit circle at z transform the X corresponding to the amplitude spectrum and phase spectrum (3) Inverse z transform sequences derived from the convergence of various jurisdictions (including the right sequence, the sequence of the left and bilateral series)