High-pass, low-pass, and notch filters each remove a distinct band of unwanted sound

Evidence

One of the simplest forms of electronic signal processing is to filter the signal in order to remove unwanted components. For example, often low-frequency noises, such as ventilation and traffic rumble, need to be removed from the signal picked up by the microphone. A high-pass filter would accomplish this, and mixing desks often provide some form of high-pass filtering for this reason. High frequencies also often need to be removed to either ameliorate the effects of noise and distortion or remove the high-frequency components that would cause alias distortion in digital systems. This is achieved via the use of a low-pass filter. A third type of filter is the notch filter, which is often used to remove tonal interference from signals. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2406

Categorization

• DEFINE: Names and defines the three basic filter types by the band each targets, the core vocabulary for any later discussion of signal processing.