Coded surveillance system having magnetomechanical marker
US4510490A · kind A · utility
129Cited by
6References
33Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1982 |
| Grant date | Apr 9, 1985 |
| Priority date | — |
| Expiry date | Jun 3, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/928
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A magnetic article surveillance system marker is adapted, when armed, to resonate at preselected frequencies provided by an incident magnetic field applied within an interrogation zone. The marker is a plurality of elongated ductile strips of magnetostrictive ferromagnetic material each of the strips being disposed adjacent to a ferromagnetic element which, upon being magnetized, magnetically biases the strips and arms them to resonate at the preselected frequencies. A substantial change in effective magnetic permeability of the marker at the preselected frequencies provides the marker with signal identity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.