线性时不变系统特性的教学方法探讨

Exploration of Teaching Method on the Characteristics of Linear Time-Invariant System

线性时不变LTI系统是一种很重要的系统,它具有4个特性:无记忆性、因果性、稳定性和可逆性。按常用的信号与系统教材中介绍的方法讲授LTI系统特性,学生不容易理解所讲授的内容。授课过程中发现,若利用卷积和的交换律,把LTI系统的输出分为3个部分:与将来的输入有关的输出、与当前的输入有关的输出和与过去的输入有关的输出;然后根据LTI系统特性的定义,结合系统的输出与输入关系,先推导离散时间LTI系统的特性,再将其结论应用到连续时间LTI系统,则LTI系统特性教师既容易讲解清楚,学生也容易理解透彻,取得了良好的教学效果。

Linear time- invariant（ LTI） system is a kind of important system. It has four characteristics such as memoryless,causality,stability and invertibility. Students are not easy to understand the system characteristics taught by teachers according to the frequently- used ＂Signals and Systems＂textbooks. It is shown that the output of LTI system can be divided into three parts,which are the outputs related to the future inputs,the outputs related to the current input,and the outputs related to the past inputs,if the commutative property of the convolution sum is used. The characteristics of the discrete- time LTI system are derived first,and the conclusion is applied to the continuous- time LTI system according to the definitions of the LTI system characteristics associated with the relationship between system outputs and system inputs. The characteristics of LTI system can be easily taught by teachers,and easy understand by students. The good teaching effect has been achieved.