Discrete-time systems

In this article we introduce digital control and contrast it with analog control. Traditionally, control systems have been designed using analog techniques. But today, because of the explosive growth of digital technology, controllers are typically implemented as programmable digital hardware or as programs on digital computers. The concepts and techniques for analysis and design of digital controllers are the central concerns of this article. In this part we introduce discrete-time signals and provide examples. We also describe discrete-time systems in terms of difference equations and look at their solutions via transform methods.