Absolute phase
Encyclopedia
Absolute phase refers to the phase
of a waveform
relative to some standard (strictly speaking, phase is always relative). To the extent that this standard is accepted by all parties, one can speak of an absolute phase in a particular field of application.
reproduction of music, absolute phase refers the phase of the reproduced sound waves relative to the original sound waves, or to the relative phase of the various channels of stereo or multi-channel reproduction. In most cases, it is actually a question of the polarity of the channels, i.e., an equal phase shift of 180° at all frequencies. Some audiophile
s claim that reversing the polarities of all the channels simultaneously makes a perceptible difference in the sound quality, even though the relative phases of all the channels are preserved. Of course, since many musical instruments produce an amount of even order harmonic distortion and so do all practical loudspeakers, reversing the phase of the recorded signal would change the harmonic distribution between odd and even harmonics.
, the phase of the voltage and current at various points in the system relative to one another are important. If the points of interest are widely separated in space, it is difficult to measure the relative phase. To solve this problem, the phase of the signals relative to absolute time (UTC) is measured using instruments relying on GPS. Comparison of two absolute phases in this sense allows the relative phase of distant signals to be computed.http://64.233.179.104/search?q=cache:jvTG0D1EGaoJ:www.arbiter.com/ftp/datasheets/1133a_absolute_phase.pdf+absolute-phase&hl=de
a pulse
or finite wavetrain can be considered as a signal of a single frequency modulated by an envelope, or as a superposition of an infinite number of infinitesimal waves of different frequencies. In the first capicture, it is a question of the relative phase of the component frequencies. For examples of physical effects due to the phase of signals with the same power spectrum.
Phase (waves)
Phase in waves is the fraction of a wave cycle which has elapsed relative to an arbitrary point.-Formula:The phase of an oscillation or wave refers to a sinusoidal function such as the following:...
of a waveform
Waveform
Waveform means the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form. In these cases, the term 'waveform' refers to the shape of a graph...
relative to some standard (strictly speaking, phase is always relative). To the extent that this standard is accepted by all parties, one can speak of an absolute phase in a particular field of application.
High fidelity
In the realm of high fidelityHigh fidelity
High fidelity—or hi-fi—reproduction is a term used by home stereo listeners and home audio enthusiasts to refer to high-quality reproduction of sound or images, to distinguish it from the poorer quality sound produced by inexpensive audio equipment...
reproduction of music, absolute phase refers the phase of the reproduced sound waves relative to the original sound waves, or to the relative phase of the various channels of stereo or multi-channel reproduction. In most cases, it is actually a question of the polarity of the channels, i.e., an equal phase shift of 180° at all frequencies. Some audiophile
Audiophile
An audiophile is a person who enjoys listening to recorded music, usually in a home. Some audiophiles are more interested in collecting and listening to music, while others are more interested in collecting and listening to audio components, whose "sound quality" they consider as important as the...
s claim that reversing the polarities of all the channels simultaneously makes a perceptible difference in the sound quality, even though the relative phases of all the channels are preserved. Of course, since many musical instruments produce an amount of even order harmonic distortion and so do all practical loudspeakers, reversing the phase of the recorded signal would change the harmonic distribution between odd and even harmonics.
Power electronics
When dealing with power electronicsPower electronics
Power electronics is the application of solid-state electronics for the control and conversion of electric power.-Introduction:Power electronic converters can be found wherever there is a need to modify a form of electrical energy...
, the phase of the voltage and current at various points in the system relative to one another are important. If the points of interest are widely separated in space, it is difficult to measure the relative phase. To solve this problem, the phase of the signals relative to absolute time (UTC) is measured using instruments relying on GPS. Comparison of two absolute phases in this sense allows the relative phase of distant signals to be computed.http://64.233.179.104/search?q=cache:jvTG0D1EGaoJ:www.arbiter.com/ftp/datasheets/1133a_absolute_phase.pdf+absolute-phase&hl=de
Signal processing
In signal processingSignal processing
Signal processing is an area of systems engineering, electrical engineering and applied mathematics that deals with operations on or analysis of signals, in either discrete or continuous time...
a pulse
Pulse (signal processing)
In signal processing, the term pulse has the following meanings:#A rapid, transient change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value....
or finite wavetrain can be considered as a signal of a single frequency modulated by an envelope, or as a superposition of an infinite number of infinitesimal waves of different frequencies. In the first capicture, it is a question of the relative phase of the component frequencies. For examples of physical effects due to the phase of signals with the same power spectrum.