This book provides the communications engineer involved in the physical layer of communications systems, the signal processing techniques and design tools needed to develop efficient algorithms for the design of various systems. These sytems inlcude satellite modems, cable modems, wire-line modems, cell-phones, various radios, multi-channel receivers, audio encoders, surveilance receivers, laboratory instruments, and various sonar and radar systems. The emphasis woven through the book material is that of intuitive understanding obtained by the liberal use of figures and examples. The book contains examples of all these types of systems. The book also will contain MATLAB script files that implement the examples as well as design tools for filters similar to the examples.