Systems and Circuits

Abstract

In this chapter we will consider systems in general, and in particular linear systems. Most systems are inherently nonlinear and time varying. A human being is a good example. He can run fast for a while and then speed comes down. If you plot speed versus time, the plot is not going to be a straight line, i.e., the function speed versus time is not linear. Humans are nonlinear and also time-varying systems. For example, if you want to ask your dad for a new car, you do not ask him when he is not happy. Moods change with time. These considerations are important in, for example, speaker identification. Human beings are not only nonlinear but also time-varying complicated systems. Nonlinear time-varying systems are very hard to deal with. Even though many of the systems may have nonlinear behavior characteristics, they can be approximated to be linear systems and they allow for transform analysis.