ABSTRACT
This chapter begins with some basic assumptions in filter analysis, followed by presenting the responses of ideal filters. It discusses first-order filters and introduces Bode plots as a very useful tool for describing the frequency response. The chapter analyses the four types of second-order responses in detail in terms of a series RLC circuit. Duality is invoked in deriving the responses to parallel first-order and second-order circuits. The chapter is concerned with the basic frequency responses of first-order and second-order circuits, with emphasis on understanding the fundamental concepts and physical interpretations behind these responses. A frequency-selective circuit or filter is a circuit intended to provide an output that varies with frequency in a desired manner. Frequency-selective circuits are an important class of electric circuits that are extensively used in communications, control, and signal processing systems. The chapter ends by examining some general features of frequency responses.
