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

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.