In an oscillator, rapid, short-term, random fluctuations in the phase of a wave, caused by time-domain instabilities.
Note: Phase noise, in decibels relative to carrier power (dBc) on a 1-Hz bandwidth, is given by = 10log[
0. 5(S(f))] where S(f) is the spectral density of phase fluctuations.

Lack of direct proportionality of phase shift to frequency over the frequency range of interest.

Synonym phase difference.

Any shifting (often quite rapid), from whatever cause, in the phase of a signal.
Note 1: The shifting in phase may appear to be random, cyclic, or both.
Note 2: The phase departure in phase perturbation usually is larger, but less rapid, than that of phase jitter.
Note 3: Phase perturbation may be expressed in degrees, with any cyclic component… (Read More →)

See quadrature.

The change in phase of a periodic signal with respect to a reference.

In the propagation of an electromagnetic wave in a uniform waveguide, such as an optical fiber or metal waveguide, the parameter that indicates the phase change per unit distance of the wave at any point along the waveguide. [From Weik '89]

Perturbations in phase of limited duration seen at synchronization interfaces. Typical duration is several time constants of the slave clock which produces them. [T1.10
5. 09-1996]

The velocity of propagation of a uniform plane wave, given by (a) the product of the wavelength and the frequency divided by (b) the refractive index of the medium in which the wave is propagating.
Note 1: In free space, the refractive index may be considered as unity.
Note 2: In free space, the group velocity and the phase velocity… (Read More →)

Binary recording on magnetic media, such as magnetic disks, tapes, and cards, in which a "1" is represented by a magnetic flux reversal to the polarity of the interblock gap, and a "0" is represented by a magnetic flux reversal to the polarity opposite to that of the interblock gap when recording in the forward direction.