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:
Feb. 25, 1992
Filed:
Jul. 31, 1989
Stephen A Roth, Aumsville, OR (US);
Roar Berg-Johansen, Salem, OR (US);
II Morrow, Inc., Portland, OR (US);
Abstract
A magnetometer and method for measuring magnetic field strength particularly adapted for use in an electronic flux gate compass. A core of magnetic material in the shape of a toroid is coupled to a drive coil and to two sense coils oriented along orthogonal axes. A current limited, current source coupled to the drive coil periodically saturates the core, drives the core out of saturation at an intermediate current level, and saturates the core again. Each sense coil is coupled to a sense circuit which measures the current in the sense coil induced by the periodically changing flux density in the coil resulting from an external magnetic field coupled to the sense coil, produces a dc feedback signal to cancel out the external magnetic field, and provides the dc signal as an output representative of the external magnetic field strength along the axis of the sense coil. The dc signal is produced by synchronously detecting the amplified ac current in the sense coil. Low pass filters are provided to eliminate ac components from the magnetometer output.