Optimal Ensembling of Ultrastable Crystal Oscillators
Conventional systems, such as satellite systems, disadvantageously use complex and expensive atomic oscillators, such as rubidium or cesium oscillators, to provide precise and stable reference frequencies. In such systems, there is a need to provide reference frequencies approaching the accuracies available from atomic standards, without using the atomic standards.
An embodiment of the present invention includes an ensemble clock or oscillator that provides an accurate output frequency. The ensemble clock comprises: an input for receiving a reference signal; multiple free-running oscillators each configured to generate a corresponding free-running frequency; an output oscillator configured to generate a controlled frequency having a frequency responsive to a control signal; a differencer unit configured to derive difference measurements indicative of time and frequency-based errors associated with each of (i) the controlled frequency, and (ii) the free-running frequency, relative to the reference signal; and a controller configured to generate the control signal responsive to the difference measurements.
Patent Status: U.S. patent(s) 7317361 issued.
Dr. G. R. Jacobovitz
Phone: (443) 778-9899