This book, Linear Systems and Signals, presents a comprehensive treatment of signals and linear systems at an introductory level. Like all my other books, it emphasizes physical appreciation of concepts through heuristic reasoning, and the use of metaphors, analogies, and creative explanations.
Such an approach is much different from a purely deductive technique that uses mere mathematical manipulation of symbols. There is a temptation to treat engineering subjects as a branch of applied mathematics. Such an approach is a perfect match to the public image of engineering as a dry and dull discipline. It ignores the physical meaning behind various derivations and deprives a student of intuitive grasp and the enjoyable experience of logical uncovering of the subject matter.
Here I have used mathematics not so much to prove axiomatic theory as to support and enhance physical and intuitive understanding. Wherever possible, theoretical results are interpreted heuristically and are enhanced by carefully chosen examples and analogies. This second edition, which closely follows the organization of the first edition, has been refined by incorporating suggestions and changes provided by various reviewers. The added topics include Bode plots, use of digital filters in an impulse-invariance method of designing analog systems, convergence of infinite series, bandpass systems, group and phase delay, and Fourier applications to communication systems.