Jump to content

Signal processor

Add links
From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by 70.50.200.239 (talk) at 03:56, 17 August 2007. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

A signal processor, in the realm of digital audio, is a device that modifies an audio signal, either electric or digital. It can be a piece of electronic hardware or computer software. A basic example of a signal processor is a high-pass filter, which removes low frequencies from a signal.

Traditionally signal processors were electronic circuits that affected analog signals. In digital audio, signal processors can be software that alter digitized audio information. The term DSP (Digital Signal Processing) usually refers to the processors that are involved in calculating the effect a digital signal processor will have on an audio file. For example, HD Accel cards by Digidesign (a leader in professional digital audio technology) contain processors that calculate the changes to a digital audio signal.


Types of Signal Processors

Equalizers (EQ)

There are various types of EQs including graphic, paragraphic, and parametric. All EQs boost or attenuate certain frequencies of an audio signal.


Dynamic Processors

Dynamics, in digital audio, refer to the changes in loudness (or amplitude) of a signal. Dynamics processors affect the dynamic range of a signal.

Compressors "turn down" the loudest parts of a signal depending on settings such as the threshold (how loud the signal has to be before the compressor starts working), attack time (how fast the compressor starts working after the threshold has been breached), release time (how quickly a signal returns to normal after the input signal is no longer over the threshold), and ratio (how much the signal should be turned down).

Expanders can be thought of as the opposite of compressors. They increase the dynamic range of an audio signal by turning down the quieter parts, or the parts that fall below the set threshold.

Limiters are compressors with ratios higher than 10:1. That is, once the signal has breached the threshold, it gets turned down severely. A brick wall limiter does not let the audio go above a certain level.

Noise gates completely turn off a signal once it has fallen below the threshold.


Reference

Audio in Media, Stanley R. Allen, Thomson Wadsworth, 7th Edition, 2005. ISBN 0-534-63046-4


This article is a stub. You can help Wikipedia by expanding it.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Signal_processor&oldid=151749607"