Time deviation
Encyclopedia
TDEV is a metric often used to determine an aspect of the quality of timing signals in telecommunication applications and is a statistical analysis of the phase stability of a signal over a given period of time. Measurements of a reference timing signal will refer to its TDEV and MTIE values, comparing them to specified masks or goals.
Time deviation (TDEV) also known as
is the time stability of phase x versus observation interval τ of the measured clock source. The time deviation thus forms a standard deviation type of measurement to indicate the time instability of the signal source. This is a scaled variant of frequency stability of Allan variance
and Allan deviation. It is commonly defined from the modified Allan deviation, but other estimators may be used.
Time variance (TVAR) also known as
is the time stability of phase versus observation interval tau. It is a scaled variant of Allan variance
.
and similarly for Allan deviation to time deviation
or the modified Allan deviation
Time deviation (TDEV) also known as
is the time stability of phase x versus observation interval τ of the measured clock source. The time deviation thus forms a standard deviation type of measurement to indicate the time instability of the signal source. This is a scaled variant of frequency stability of Allan varianceAllan variance
The Allan variance , also known as two-sample variance, is a measure of frequency stability in clocks, oscillators and amplifiers. It is named after David W. Allan. It is expressed mathematically as\sigma_y^2. \,...
and Allan deviation. It is commonly defined from the modified Allan deviation, but other estimators may be used.
Time variance (TVAR) also known as
is the time stability of phase versus observation interval tau. It is a scaled variant of Allan varianceAllan variance
The Allan variance , also known as two-sample variance, is a measure of frequency stability in clocks, oscillators and amplifiers. It is named after David W. Allan. It is expressed mathematically as\sigma_y^2. \,...
.
Definition
The time variance and time deviation is defined as scaled Allan variance and Allan deviation, which provides the frequency stability variance and deviation.and similarly for Allan deviation to time deviation
Estimators
The most common estimator uses the modified Allan varianceModified Allan variance
The modified Allan variance , also known as mod σy2, is a variable bandwidth modified variant of Allan variance, a measurement of frequency stability in clocks, oscillators and amplifiers...
or the modified Allan deviation
Modified Allan variance
The modified Allan variance , also known as mod σy2, is a variable bandwidth modified variant of Allan variance, a measurement of frequency stability in clocks, oscillators and amplifiers...