Essential Guide to Digital Signal Processing, The

8. Digital Filters

In previous chapters, we mentioned the idea of filtering analog and digital signals. Because filtering is a crucial operation in all voice communications, music, and video signal processing systems, let’s learn more about filters and filtering.

The word filter means just what you might expect—a device that allows certain things to pass through and blocks other things. For example, the paper filter in your electric coffee maker allows water to pass through but blocks the coffee grounds. The air filter in your automobile allows air to pass through to your car’s engine but blocks any dust particles.

Instead of water or air, let’s talk about electronic filters that allow certain signal frequencies to pass and block other signal ...