| 摘要 |
A dual status magnetic marker for use in electronic article surveillance systems, in which a piece of low coercive force, high permeability material is positioned adjacent to a piece of remanently magnetizable material. The first piece is configured such that no characteristic response is produced when the magnetization of the entire piece is reversed by an alternating magnetic field in an interrogation zone, and when the second piece is magnetized with a predetermined pattern a localized field is provided which biases portions of the first piece, keeping those portions from reversing when the marker is in the interrogation field. The predetermined pattern is such that the remaining, unbiased portion of the first piece has a configuration capable of producing a characteristic response when the magnetization in that portion is reversed. |
