Clock stability measure dependence on time error sampling period

Abstract

The introduction of SDH based networks rises new important synchronization issues to be carefully investigated. In particular, the telecommunication standard bodies are mainly considering, for the specification of clocks, five frequency stability quantities: Allan (1991) variance, modified Allan variance, time variance, root mean square of the time interval error and maximum time interval error. The influence of time error measurement sampling period on the behaviour of these quantities is analyzed. Computer simulation and experimental measurement results are reported. With the aim of providing useful information for specification design. The results obtained show that the modified Allan variance and time variance behaviour is substantially dependent on the chosen measurement sampling period in the observation interval regions where white phase noise dominates.