说明：  该程序包含st原程序和使用st变换的一个程序，st源程序需要加入matlab的toolbox下，sst程序为自己编写的应用例程，希望对初学者有帮助
(St includes the program and use the original procedure st transform a program, st source matlab need to join the toolbox under, sst procedure to prepare the application for their own routine, and they hope to be helpful for beginners)