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. 23, 1993
Filed:
Jan. 09, 1992
Applicant:
Inventors:
Harry E Watkins, Boca Raton, FL (US);
David L Roberson, Forest, VA (US);
Assignee:
Sensormatic Electronics Corporation, Deerfield Beach, FL (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340572 ; 340551 ;
Abstract
A method and apparatus for determining the amplitude of a first magnetic field at a first fundamental frequency in a zone in which a second magnetic field is able to be present wherein first and second transmissions of a magnetic field at the fundamental frequency and different phases is carried out at different times, the field in the zone is detected for each transmission and the detected fields are processed to determine the magnitude of the first magnetic field.