控制理论：数字控制 z变换

RELATIONSHIP BETWEEN S/Z PLANES AND TIME DOMAIN：http://controlsystemsacademy.com/0003/0003.html#ch1，含在线仿真器

An s-Plane to z-Plane Mapping Example：https://www.dsprelated.com/showarticle/994.php，给出一一对应的关系

Conformal Mapping between S-Plane to Z-Plane，http://fourier.eng.hmc.edu/e102/lectures/Z_Transform/node2.html，数学上做了分析