ABSTRACT
The digital control system analysis and design methods are proceeded as if the controller signals and coefficients were of continuous amplitude. However, because digital controllers are implemented with finite word length (FWL) registers and finite precision arithmetic, their signals and coefficients can attain only discrete values. Therefore, further analysis is needed to determine if the performance of the resulting digital controller in the presence of signal and coefficient quantization is acceptable. The chapter discusses three error sources that may occur in digital processing of controllers. These error sources are coefficient quantization, quantization in A/D conversion, and arithmetic operations. The chapter describes about the limit cycles and deadbands. There are many choices of arithmetic that can be used to implement digital controllers. Because of the FWL of registers in digital computers, errors are always introduced when the numbers to be processed are quantized. The digital control system design methods resulted in controllers whose coefficients are of arbitrary precision.
