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:
Jan. 02, 1990
Filed:
Mar. 09, 1989
Marvin E Frerking, Cedar Rapids, IA (US);
Rockwell International Corporation, El Segundo, CA (US);
Abstract
In order to compensate for mechanical vibration that corrupts the RF output spectrum of a crystal oscillator, three accelerometers are mounted with the oscillator and aligned on mutually perpendicular axes. The outputs of the accelerometers are digitized and applied to adaptive transversal filters comprising a digital signal processor. The crystal oscillator is placed on a vibration table and its output is compared with an external frequency reference. The tap weights of the filters are then optimized so that the vibration components of the output spectrum of the oscillator are minimized. After the tap weights of the filters are determined and fixed, the filters provide vibration compensation for the oscillator. During operation of the crystal oscillator, the outputs of the filters are summed and applied to a varactor in the oscillator to compensate the output for the effects of mechanical vibration.