IEEE-SPS/Connexions Project aims to provide High-quality open-access educational content for students, instructors, practitioners, and the developing world. For examples of collections in Connexions, please see “Digital Signal Processing: A User’s Guide” collection. This collection is intended both for the practicing engineer with a basic knowledge of DSP and for a second course in signal processing at the senior or first-year postgraduate level. FFTs, digital filter design, adaptive filters, and multirate signal processing are covered with an emphasis on the techniques that have found wide use in practice.