Understanding complex numbers and quadrature signals is essential for understanding DSP at both a theoretical and a practical level. Yet this strange, complex subject (based on the admittedly imaginary construct of the square root of negative one!) is among the hardest for DSP beginners to grasp - and is confusing at times even for advanced DSPers.
But don't despair: help is on the way. In this tutorial, Rick Lyons, author of the best-selling DSP books Understanding Digital Signal Processing and Streamlining Digital Signal Processing: A Tricks of the Trade Guidebook, clears the fog around this difficult subject by providing the clearest, most intuitive explanation yet of quadrature signals and their importantance in Digital Signal Processing.