An alteration of the phase in the partials of a tone. Virtually all signal processing devices will cause a certain amount of phase-shift, also called phase modulation, as none of them are completely phase linear. Phase-shift is a characteristic of a device and is the change in phase impressed on a signal that passes through the device. An electronic device will always add a time delay to an applied signal. If the time delay is constant on all frequencies, the phase-shift between the input and output of the device will be a linear function of frequency, and the device is called phase linear. Deviations from phase linearity are called phase-shift. Equalizers, in particular, exhibit large amounts of phase-shift. In a complex waveform, phase-shift will cause a distortion of the waveform, even though the frequency response curve may be perfectly flat. There is considerable controversy over whether the ear can detect this type of phase distortion.
See also PIM.« Back to Glossary Index