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:
Apr. 17, 2012
Filed:
Feb. 19, 2010
Geoffrey Bainbridge, Ottawa, CA;
Nicholas Jason Ackerley, Kanata, CA;
Geoffrey Bainbridge, Ottawa, CA;
Nicholas Jason Ackerley, Kanata, CA;
Nanometrics Inc., Kanata, Ontario, CA;
Abstract
A broadband weak-motion seismometer includes: a frame, a mass, a suspension means for movably connecting the mass to the frame, a sensing transducer for measuring displacement of the mass with respect to the frame and for generating a sensing transducer output signal, which is a function of the measured displacement, a forcing transducer for applying a feedback force in a predetermined direction to the mass, and a control circuit. The control circuit receives the sensing transducer output signal and generates a forcing transducer input signal that includes a self-noise component. The forcing transducer input signal is processed by the forcing transducer to apply the feedback force to maintain the mass at rest with respect to the frame. The feedback force is sufficient to counterbalance a constant acceleration of the frame of at least 0.2 m/sin the predetermined direction of the feedback force. The self-noise component of the forcing transducer input signal, when processed by the forcing transducer, produces variable acceleration of the mass with spectral density less than −150 dB with respect to 1 m/sat 0.01 Hz.