Signals and systems 2nd by Openheim

For undergraduate-level courses in Signals and Systems. This comprehensive exploration of signals and systems develops continuous-time and discrete-time concepts/methods in parallel highlighting the similarities and differences and features introductory treatments of the applications of these basic methods in such areas as filtering, communication, sampling, discrete-time processing of continuous-time signals and feedback. Relatively self-contained, the text assumes no prior experience with system analysis, convolution, Fourier analysis or Laplace and z-transforms