Part of the Computing fundamentals glossary:

Linearity is the behavior of a circuit, particularly an amplifier , in which the output signal strength varies in direct proportion to the input signal strength. In a linear device, the output-to-input signal amplitude ratio is always the same, no matter what the strength of the input signal (as long it is not too strong).

In an amplifier that exhibits linearity, the output-versus-input signal amplitude graph appears as a straight line. Two examples are shown below. The gain, or amplification factor, determines the slope of the line. The steeper the slope, the greater the gain. The amplifier depicted by the red line has more gain than the one depicted by the blue line. Both amplifiers are linear within the input-signal strength range shown, because both lines in the graph are straight.

 

Illustration of linearity (2292 bytes)


In analog applications such as amplitude-modulation ( AM ) wireless transmission and hi-fi audio, linearity is important. Nonlinearity in these applications results in signal distortion, because the fluctuation in gain affects the shape of an analog output waveform with respect to the analog input waveform.

Even if an amplifier exhibits linearity under normal conditions, it will become nonlinear if the input signal is too strong. This situation is called overdrive. The amplification curve bends towards a horizontal slope as the input-signal amplitude increases beyond the critical point, producing distortion in the output. An example is a hi-fi amplifier whose gain is set to the point where the VU (volume-unit) meter needles kick into the red range. The red zone indicates that the amplifier is not operating in a linear fashion. This can degrade the fidelity of the sound.

This was last updated in June 2010
Posted by: Margaret Rouse

Related Terms

Definitions

  • Schrodinger's cat

    - Schrodinger's cat explained: This definition describes Schrodinger's famous thought experiment and its place in quantum theory. (WhatIs.com)

  • flash storage

    - Flash storage, based on flash memory, is used for data repositories, storage systems and consumer devices, such as USB drives, smartphones and solid-state drives. Flash-based storage is faster than... (WhatIs.com)

  • six degrees of separation

    - Six degrees of separation is the theory that anyone on the planet can be connected to any other person on the planet through a chain of acquaintances that has no more than five intermediaries. (WhatIs.com)

Glossaries

  • Computing fundamentals

    - Terms related to computer fundamentals, including computer hardware definitions and words and phrases about software, operating systems, peripherals and troubleshooting.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question. Find an Answer.Powered by ITKnowledgeExchange.com

Ask An IT Question

Get answers from your peers on your most technical challenges

Ask Question

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.