Patent ID: 9390602
Filing Date: 2016-07-12
CPC Classification: E05B,G08B

Claim Text:
1. A method for verifying a detachment of a security tag from an article, comprising: concurrently producing, by a detaching unit, a first signal at a first frequency and a second signal at a second frequency when the security tag is in proximity to the detaching unit, the detaching unit operative to detach the security tag from the article; performing operations by a non-linear frequency mixer circuit disposed within the security tag to generate a third signal from mixing the first and second signals applied thereto by the detaching unit, where the non-linear frequency mixer is exclusive of an Electronic Article Surveillance (“EAS”) element disposed within the security tag; ceasing generation of the third signal by the non-linear frequency mixer circuit when a first portion of the security tag is moved a certain distance from the detaching unit; and determining by the detaching unit that the first portion of the security tag has been decoupled from a second portion of the security tag when the third signal is no longer being generated by the non-linear frequency mixer circuit.