Nonlinear distortion

Nonlinear distortion

Nonlinear distortion is a term used (in fields such as electronics, audio and telecommunications) to describe the phenomenon of a non-linear relationship between the "input" and "output" signals of - for example - an electronic device.

Model

For many devices, a linear model is accurate only for small signal levels. For example, at 2 volts input, a typical audio amplifier might put out 20 V, meaning the linear gain is 10 V/V. For 3 V input, it might then output 30 V. However, the model implies that at 50 V input it would produce 500 V, which is not possible with most amplifiers.

Mathematically, the input-output relationship of many devices should be described by a polynomial or Taylor series, as shown below.

v = \sum_{k=1}^\infty a_ku^k

For larger values of u, the higher order coefficients such as a2 and a3 come into play.

Effects of nonlinearity

Nonlinearity can have several effects, which are unwanted in typical situations. The a3 term for example would, when the input is a sine wave with frequency ω, result in an extra sine wave at , as shown below.

v = (a_1 + \frac{3}{4}a_3) sin(\omega t) - \frac{1}{4}a_3 sin(3\omega t)

In certain situations, this spurious signal can be filtered away because the "harmonic" lies far outside the frequency range used, but in cable television, for example, third order distortion could cause a 200 MHz signal to interfere with the regular channel at 600 MHz.

Nonlinear distortion applied to a superposition of two signals at different frequencies causes the circuit to act as a frequency mixer, creating intermodulation distortion.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • nonlinear distortion — netiesinis iškraipymas statusas T sritis automatika atitikmenys: angl. nonlinear distortion vok. nichtlineare Verzerrung, f rus. нелинейное искажение, n pranc. distorsion non linéaire, f …   Automatikos terminų žodynas

  • nonlinear distortion — noun distortion that occurs when the output signal does not have a linear relation to the input signal • Syn: ↑amplitude distortion • Hypernyms: ↑distortion …   Useful english dictionary

  • Nonlinear X-wave — schematic view In physics, a nonlinear X wave (NLX) is a multi dimensional wave that can travel without distortion. At variance with X waves, a nonlinear X wave does exist in the presence of nonlinearity, and in many cases it self generates from… …   Wikipedia

  • Distortion (optics) — v · d · e Optical aberration …   Wikipedia

  • Distortion — This article is about technology, especially electrical engineering. For other uses, see Distortion (disambiguation). Distort redirects here. For other uses, see Distort (disambiguation). A distortion is the alteration of the original shape (or… …   Wikipedia

  • Nonlinear X-waves — In physics, a Nonlinear X wave (abbr. NLX) is a multi dimensional wave which can travel without distortion.At variance with X waves, a Nonlinear X wave does exist in the presence of nonlinearity, and in many cases it self generates from a… …   Wikipedia

  • amplitude distortion — noun distortion that occurs when the output signal does not have a linear relation to the input signal • Syn: ↑nonlinear distortion • Hypernyms: ↑distortion …   Useful english dictionary

  • Amplitude Distortion — F/A/V The nonlinear relation of input and output induced harmonics which is a function of voltage fluctuations or power consumption. (Acoustics) …   Audio and video glossary

  • Sound from ultrasound — Contents 1 Parametric array 2 Applications 2.1 Commercial advertising …   Wikipedia

  • Comparison of analog and digital recording — This article compares the two ways in which sound is recorded and stored. Actual sound waves consist of continuous variations in air pressure. Representations of these signals can be recorded using either digital or analog techniques. An analog… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”