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:
Sep. 02, 1986
Filed:
Jul. 19, 1985
Applicant:
Inventors:
Gary E Nourse, Osceola, WI (US);
Dean M Dowdle, White Bear Lake, MN (US);
Assignee:
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340572 ; 343 / ;
Abstract
An electronic article surveillance system is disclosed, having a transmitter means for producing in an interrogation zone sequences containing a plurality of discrete different radio frequencies thereby causing a circuit present within the zone to resonate at its resonant frequency in response to energy absorbed at at least three different frequencies. A receiver means is provided to cause an alarm in the event of detection of three such resonances over two successive sequences.