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. 14, 1987
Filed:
Sep. 17, 1985
John J Torre, Monroe, NY (US);
Allied Corporation, Morris Township, Morris County, NJ (US);
Abstract
An article surveillance system includes a structure responsive to a first pulsed inductive magnetic field, periodically derived by a power line activated generator. The structure derives a second pulsed inductive magnetic field having a predetermined occurrence time relative to the occurrence time of the first magnetic field. A receiver for the second magnetic field is power line activated. The occurrence time of the first magnetic field and the activation time of the receiver to be responsive to the second magnetic field are synchronized. The synchronization of the transmitter and receiver is provided by separate zero crossing detectors for the power lines respectively activating the transmitter and receiver. The power lines activating the transmitter and receiver are likely to have zero crossings at different predetermined time positions because they are likely to be across two different phases of a three-phase power line. The receiver and transmitter includes separate circuits for compensating for the different zero crossing time positions.