Electronic article surveillance system with adaptive filtering and digital detection

US5602531A · kind A · utility

Assignee

• Minnesota Mining and Manufacturing Company · US

Inventors

• Michael John Rude · Minnetonka, US
• Samuel H. Tao · Woodbury, US
• John E. Nelson · Eden Prairie, US

Key dates

• Filing date: May 7, 1996
• Grant date: Feb 11, 1997
• Expiry date: May 7, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G08B13/2488
• WIPO field: Control
• WIPO sector: Instruments

Abstract

An electronic article surveillance (EAS) systems includes an asynchronous noise suppression adaptive filter which removes asynchronous interference from the signal of interest with minimum distortion of the transients emitted when a sensitized tag is interrogated. The system also includes a synchronous noise suppression filter which removes interrogation synchronous noise from the signal of interest. The resulting EAS system increases the likelihood that a sensitized tag will be detected when one is present and reduces the occurrence of false alarms.