What is nonlinearity? - Definition from WhatIs.com
Part of the Electronics glossary:

Nonlinearity is the behavior of a circuit, particularly an amplifier, in which the output signal strength does not vary in direct proportion to the input signal strength. In a nonlinear device, the output-to-input amplitude ratio (also called the gain) depends on the strength of the input signal.

In an amplifier that exhibits nonlinearity, the output-versus-input signal amplitude graph appears as a curved line over part or all of the input amplitude range. Two examples are shown below. The amplifier depicted by the red curve has gain that increases as the input signal strength increases; the amplifier depicted by the blue curve has gain that decreases as the input signal strength increases.


Illustration of nonlinearity (2568 bytes)

Nonlinearity can be tolerated in devices and systems that use digital modulation, and also in frequency modulation (FM) wireless transmitters. These signals are either full-on or full-off; the amplitude waveforms are not analog, so analog distortion cannot occur. In analog devices and systems, however, linearity is important. Nonlinear circuits generally cause distortion in applications such as amplitude-modulation (AM) wireless transmission and hi-fi audio.

This was last updated in May 2008
Posted by: Margaret Rouse

Related Terms


  • laser

    - A laser is a coherent and focused beam of photons; coherent, in this context, means that it is all one wavelength, unlike ordinary light which showers on us in many wavelengths. The acronym laser s... (WhatIs.com)

  • photon

    - In some ways, visible light behaves like a wave phenomenon, but in other respects it acts like a stream of high-speed, submicroscopic particles. (WhatIs.com)

  • IR LED (infrared light-emitting diode)

    - An IR LED (infrared light emitting diode) is a solid state lighting (SSL) device that emits light in the infrared range of the electromagnetic radiation spectrum. (WhatIs.com)


  • Electronics

    - Terms related to electronics, including definitions about electrical components and words and phrases about computers, laptops parts, digital cameras, televisions and home appliances.

  • 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



    Contribute to the conversation

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