ABSTRACT
This chapter explains the significance of sampling, quantization and data interpolation in computer-based control systems. It introduces the z-transform as a model of discrete signals and the difference equation as a model of discrete linear systems. The chapter explores discrete integrators, differentiators and filters, discusses the concept of the transfer function to discrete linear systems and presents z-plane pole-zero models. The widespread adoption of information technology in industrial process plant and manufacturing systems has enabled individual digital control loops to be integrated into complex, computer-based management systems. The processes of sampling, quantization and data interpolarization have a profound effect on the behaviour of a digital control system. Sampling and quantization together are often referred to as digitization. One important practical consequence of aliasing is that high-frequency noise present in a transducer output signal may be misinterpreted as much lower-frequency variations in the measurad.
