Distortion

A distortion is the (usually) undesirable alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. Distortion is sometimes denoted as the amount of difference between the entity's orignal shape and its altered shape and can be quantified as a percentage of the magnitude of the original entity.

Examples of distortion

Map projections

Some distortions are also misrepresentations. The Mercator projection in cartography, for example, distorts Greenland because of its high latitude, in the sense that its shape is not that on a globe.

Related Topics:
Misrepresentation - Mercator projection - Cartography - Greenland - Latitude - Globe

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Electronic signals

In telecommunication and signal processing, distortion occurs when the output of a "system" is different from what is expected under ideal circumstances. A system is often characterized by a transfer function, a mathematical model of how we expect things to change as they pass through the system. These models often rely on assumptions that are not entirely correct, and the true behavior of the system is often different than what the mathematics suggest. Nonlinearities in the transfer function of an active device (ie, vacuum tubes, transistors, and operational amplifiers) are a common source of distortion; in passive components (such as a coaxial cable or optical fiber), distortion can be caused by inhomogeneities, reflections, etc, in the propagation path.

Related Topics:
Telecommunication - Signal processing - System - Transfer function - Nonlinearities - Active device - Vacuum tube - Transistor - Operational amplifier - Component - Coaxial cable - Optical fiber - Inhomogeneities - Reflections - Propagation - Path

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Amplitude distortion

Frequency distortion

Phase distortion

Group delay distortion

Teletypewriter signaling

In start-stop teletypewriter signaling, distortion is the shifting of the significant instants of the signal pulses from their proper positions relative to the beginning of the start pulse. The magnitude of the distortion is expressed in percent of an ideal unit pulse length.

Related Topics:
Teletypewriter - Signaling - Pulse

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:Source: from Federal Standard 1037C in support of MIL-STD-188

Related Topics:
Federal Standard 1037C - MIL-STD-188

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Audio distortion

In this context, distortion refers to any kind of deformation of a waveform, compared to an input. clipping, compression, non-linear behavior of electronic components, modulation and mixing phenomena or power supply inefficiencies can cause distorion.

Related Topics:
Clipping - Compression - Modulation - Mixing

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In fuzzboxes and solid state distortions, the signal is boosted, and the tops of the waveform clipped off. In vacuum tube distortion, or tube modelling distortion, the top of the wave form is compressed, thus giving a smoother distorted signal, that retains more of the data in the original waveform. This is generally considered more pleasing to the ear (see tube sound). This is commonly referred to as overdrive, as it was originally (and still is) attained by driving the tubes in an amplifier a little harder than they can handle without affecting the signal.

Related Topics:
Fuzzbox - Boost - Tube sound - Overdrive

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Guitar distortion

Within the world of guitar music and guitar amplification, distortion is a type of effect that is commonly used with guitars, particularly within rock and heavy metal. This is a specific application of the above definition. There are three main ways to achieve distortion - either from the amplifier (sometimes from the preamplifier), from a stomp box or from realtime working software (Digital_signal_processing on PC).

Related Topics:
Guitar - Rock - Heavy metal - Amplifier - Preamplifier - Stomp box - Digital_signal_processing

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