Time- and Frequency-Domain Characteristics of Linear Time-Invariant Systems

Abstract

The purpose of this chapter is twofold. First, we explain how a linear time-invariant system acts in the frequency domain. An important feature of such systems is that (in an input/output setting) they transform sinusoidal (and, more generally, exponential) inputs into sinusoidal (exponential) outputs. This leads to the transfer function and the frequency response as a convenient way of describing such systems. The second purpose of this chapter is to study properties of the time- and frequency-domain response. Thus we describe important characteristics of a system that can be deduced from its step-response, or from its Bode and Nyquist plots.