发明名称 |
Balanced field theft detection system |
摘要 |
Apparatus and method for identifying the presence in a pre-established location of an object having preselected electrical or magnetic properties. By applying two periodically varying electro-magnetic fields of the same frequency to the pre-established location, the presence of the object is determined by unique perturbations of the electro-magnetic fields produced by the object. The applied electro-magnetic field is generally nonuniform in the pre-established location to maximize the interaction between the object and the electro-magnetic field. A pick-up coil is utilized to sense the resulting field perturbations. A magnetometer can be optionally incorporated in a sensing system to inhibit erroneous indications produced by magnetic objects.
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申请公布号 |
US4063230(A) |
申请公布日期 |
1977.12.13 |
申请号 |
US19750586333 |
申请日期 |
1975.06.12 |
申请人 |
MAGNAVOX CO |
发明人 |
HOLZINGER C;PURINTON E;AUGER R |
分类号 |
G08B13/24;(IPC1-7):G08B13/24 |
主分类号 |
G08B13/24 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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