This series of lessons builds on several of the concepts introduced in the Foundations series. It concerns time-domain descriptions for the characteristics of linear, time-invariant (LTI) systems. You will learn the origins and properties of convolution for describing LTI systems in terms of the impulse response and a procedure for evaluating convolution. You will also learn how differential and difference equations are used to represent LTI systems and what they reveal about system behavior. If you have no prior experience with LTI systems, then this series is designed to efficiently teach you the knowledge you need for future study.