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:
Aug. 14, 1984
Filed:
May. 07, 1982
Richard A Sparks, Bedford, MA (US);
Raytheon Company, Lexington, MA (US);
Abstract
Bodies of a ferrimagnetic material are disposed within small cavities provided in a magnetometer. The magnetometer is initially calibrated utilizing an electromagnet to produce an applied magnetic field of either known field strength, H.sub.DC, or known field distribution. Radio frequency energy is fed equally to each cavity and each material and results in resonance frequency output signals which may be coupled to a visual display. When the calibrating magnetic field is of known uniform strength, H.sub.DC, the orientation of the bodies is changed until each of the resonance signals have a frequency substantially given by f.sub.c =.gamma.H.sub.DC where .gamma.=2.8 MHz/oersted. When the calibrating magnetic field has a known field distribution the orientation of bodies is changed until such resonance signals have frequencies related to one another in accordance with the relative magnetic field strengths passing through the cavities. After calibration, the electromagnet is replaced by a test fixture including a magnet, the magnetic properties of which are to be measured. Radio frequency energy signals are reintroduced into the cavities. The frequency (f.sub.M) of each of the output signals is then measured. The strength of magnetic field (H.sub.M) of the permanent magnet passing through the cavities is calculated in accordance with H.sub.M =f.sub.M /.gamma.. The distribution of the magnetic field of the magnet under evaluation is determined by comparing frequencies of the output signals.