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Author: Hans Lohninger

A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation.

Amplitude distortion Amplitude distortion is distortion occurring in a system, subsystem, or device when the output amplitude is not a linear function of the input amplitude under specified conditions.
Frequency distortion This form of distortion occurs when different frequencies are amplified by different amounts, mainly caused by combination of active device and components. For example, the non-uniform frequency response curve of RC-coupled cascade amplifier is an example of frequency distortion.
Phase distortion This form of distortion mostly occurs due to the reactive component, such as capacitive reactance or inductor capacitance. Here, all the components of the input signal are not amplified with the same phase shift, hence causing some parts of the output signal to be out of phase with the rest of the output.
Group delay distortion Can be found only in dispersive media. In a waveguide, propagation velocity varies with frequency. In a filter, group delay tends to peak near the cut-off frequency, resulting in pulse distortion.

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Last Update: 2009-11-01