One of the best resources to learn about DSP can be found here which conatins a full book on the subject.
“What is Digital Signal Processing? -The world of science and engineering is filled with signals: images from remote space probes, voltages generated by the heart and brain, radar and sonar echoes, seismic vibrations, and countless other applications. Digital Signal Processing is the science of using computers to understand these types of data.”
from The Scientist and Engineer’s Guide to Digital Signal Processing
Each application of DSP techniques requires quite different types of interpretation. We use DSP techniques in our [[glossary:ct|disk imaging tool] with algorithms developed for the interpretation of the analogue signals contained on magnetic media.