Phase Noise Impact on the Short-Term Frequency Stability of a Frequency Source

Abstract

The impact of phase noise on the short-term frequency stability (i.e. the Allan deviation with smaller averaging time) of a frequency source has been discussed in detail in the paper. The paper also describes a technique to estimate the Allan deviation values of a frequency source from its measured phase noise plot. Using the technique described here, the Allan deviations of a 10 MHz Rubidium Atomic Frequency Source (RAFS) of an IRNSS (Indian Regional Navigation Satellite System) satellite have been estimated. The estimated Allan deviation values thus obtained from the measured phase noise plot of the RAFS are then compared with the measured Allan deviation values obtained by standard methods (such as the Standard Reference Source method and the 3-Corner Hat method) during Integrated Spacecraft Testing of the IRNSS satellites.