| Abstract: |
A novel, all-digital phase measurement system, to be utilized as part of the NIST Time Scale at NIST in Boulder, CO is presented. The system is used to compare output signals from several commercial atomic frequency standards: the phase differences between these signals, at different measurement times, are then input to the algorithm used to generate the NIST Time Scale. Preliminary results from common-clock measurements show a time deviation {sigma]x(τ) < 6 10-13s for measurement times up to 2000 seconds and below 1 ps for measurement times up to 10,000 seconds. Within these measurement times, and up to 250,000 seconds, the performance of the system is thus better than or comparable to existing commercially available systems. Time differences measurements performed by the novel system resulted coincident to the ones performed by the commercial unit presently implemented in UTC(NIST) in within a part in 1017, thereby validating its performance capabilities. |
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