Knogo Corporation

Kyung-Ho Shin

Peter Y Zhou

Michael N Cooper

Thomas P Solaski

Charles D Graham

Y Peter Zhou

Jeffrey Taegue

John Dunn

A responder for electronic article surveillance apparatus is made by subjecting a plurality of magnetizable elements to heating in the presence of a magnetic field and maintaining the field at a different intensity for each element as it is cooled to provide different magnetic characteristics so that when the responder is subjected to a cyclically varying magnetic interrogation field its several elements produce spaced apart pulses in each cycle.

Multiple pulse responder and detection system and method of making and

A novel sensor element having low magnetic coercivity and an asymmetric hysteresis characteristic is formed by heating a strip of cobalt alloy in an exidizing atmosphere to form an oxide coating thereon and then the strip is cooled in the presence of a magnetic field of about 0.3 oersteds along its length. The strip is detected by subjecting it to an alternating magnetic interrogation field and passing the resulting magnetic disturbances through signal processing circuits which select pulses produced only once in each interrogation field cycle. The element is deactivated by subjecting it to a magnetic field which eliminates its asymmetry.

Electromagnetic sensor element and methods and apparatus for making and

Growing community of inventors

Lattingtown, NY, United States of America

Kyung-Ho Shin