, is the time stability of phase versus observation interval tau.
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.
Measurements of a reference timing signal will refer to its TDEV and maximum time interval error (MTIE) values, comparing them to specified masks or goals.
[Add definitions of n and τ0] The 3 in the denominator normalizes TVAR to be equal to the classical variance if the deviations in x are random and uncorrelated (white noise).
Alternatively, TDEV, which is the square-root of TVAR, may be derived from MDEV modified Allan deviation