应用算法建立模型并编写程序，实现对系统原始函数的识别。程序为对一四阶传递函数的识别，通过修改扫描频率可获得不同趋近原始系统的传递函数。-Applied algorithm model and program, realize the original function of system identification. Procedures for the transfer function of matters order by modifying scan frequency identif