The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 2002
Filed:
Dec. 14, 2000
Tod A. Oblak, Pittsburgh, PA (US);
Harvey C. Nathanson, Pittsburgh, PA (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
An atomic clock of the type having a cell filled with an active vapor through which is projected a light beam. A detector of the projected light provides corresponding detector signals to a microprocessor. An rf frequency synthesizer provides a microwave signal to a microwave cavity adjacent the cell and also provides a clock standard output signal. The rf frequency synthesizer includes a fractional-N frequency synthesizer which compares signals from a voltage controlled crystal reference oscillator and a voltage controlled oscillator. The fractional-N frequency synthesizer is operable to provide an output control signal to precisely lock the voltage controlled oscillator microwave output signal with the voltage controlled crystal reference oscillator signal. The fractional-N frequency synthesizer also periodically causes a predetermined desired dither in the microwave signal.