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RF reactivatable marker for electronic article surveillance system

  • US 4,745,401 A
  • Filed: 09/09/1985
  • Issued: 05/17/1988
  • Est. Priority Date: 09/09/1985
  • Status: Expired due to Term
First Claim
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1. In an electronic article surveillance system having a receiver for detecting oscillations from a tuned resonant circuit;

  • a resensitizable marker comprising therein, an inductive-capacitive resonant circuit, a first magnetic material, and means for controlling a magnetic circuit formed by said first material, wherein said resonant circuit includes an inductive component having one or more turns, said first magnetic material includes at least one piece of magnetic material of a first type having a low coercive force and high permeability and substantially encloses only a portion of said one or more turns of said inductive component, and said means for controlling the magnetic circuit formed by said material of the first type causes the resonant circuit to alternately be in a first sensitized state and a second, desensitized state.

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