Signals and systems is a fundamental book focusing on basics that other advanced books of engineering subjects are based on. It introduces systems theory covering all the concept of systems. It also studies signals and their interaction with physical systems.mathematical representation between input and output signals is known as systems in four domains: time, frequency, s and z. This is a comprehensive book on signals and systems which explains continuous time and discrete time concepts parallelly and highlights their similarities and differences. It also describes the application of these basic methods in areas such as sampling, filtering, communication, discrete-time processing of continuous-time signals and feedback. This book covers the topics such as linear time-invariant systems, fourier series representation of periodic signals, the continuous-time fourier transform, the discrete-time fourier transform, time and frequency characterization of signals and systems, sampling. Communication systems, the laplace transform, the z-transform, linear feedback systems etc. The author explains all the theories with plenty of examples. Although this book does not have any pre-requisite, it is still required to have a good understanding of calculus, complex numbers and elementary differential equations to understand all the topics it comprises. This book is highly recommended for the students who believe in self-study.this book is very helpful for a two or three semester undergraduate course in signals and linear systems theory and applications. It was published by prentice-hall in 1997 and is available in paperback. Key features: the book is a comprehensive study of signals and systems. It requires no pre-requisite and is relatively self-contained. - from Amzon