Simplified Three-Cornered-Hat Technique for Frequency Stability Measurements

Abstract

We propose a novel technique allowing the use of the three-cornered-hat method with two devices under test (DUTs) and a time-tagging system that employs a common reference oscillator. The precision of a time-tagging system is reduced by fluctuations in the timebase, which are canceled when the relative phase between the two DUTs is measured. However, the raw time-tags in this system provide a phase comparison between the DUTs and the system timebase, allowing the use of the three-cornered hat with some dual-channel measurement instruments.