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:
Jun. 25, 1996
Filed:
May. 25, 1995
John R Vig, Colts Neck, NJ (US);
Raymond L Filler, Lebanon, NJ (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
The present invention provides for methods of increasing the frequency vs. temperature ('f vs. T') stability of Oven Controlled Crystal Oscillators to levels which are superior to atomic frequency standards and 100 to 10,000 times higher than that currently available from the best crystal oscillators. This method encompasses the steps of making an SC-cut quartz resonator with upper and lower turnover temperatures at or near the resonator's inflection temperature, inserting the resonator into a high-stability oscillator circuit, placing the circuit into a high-stability, high thermal gain oven and adjusting the oven temperature to a set-point at or near one of the resonator's turnover temperatures. A preferred embodiment of the method of the present invention is also disclosed which comprises forming an SC-cut quartz resonator with upper and lower turnover temperatures within 10 K of the resonator's inflection temperature, inserting the resonator into a dual-mode high-stability oscillator circuit which is placed in an oven having a thermal gain exceeding 5,000 and temperature fluctuations smaller than 50 mK and utilizing a thermometric beat frequency of said resonator to adjust the oven temperature to a set-point within 100 mK of the lower turnover temperature.