"Discrete Time Signal Processing" by AlanOppenheim and RonaldSchafer (ISBN: 0137549202 ). One of the classic introductory textbooks into DigitalSignalProcessing. Now in its second edition. Excellent book. Focuses on elementary DigitalSignalProcessing theory, including discrete signal transforms (DFT, Z-transform, FFT), digital filtering (FIR, IIR), sampling and reconstruction theory, etc.
Discrete Time Signal Processing
last modified: February 27, 2004