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公开(公告)号：US4063230A
公开(公告)日：1977-12-13
申请号：US586333
申请日：1975-06-12
IPC分类号： G08B13/24
CPC分类号： G08B13/2471
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.
摘要翻译： 用于识别在具有预选的电或磁特性的物体的预先建立的位置中的存在的装置和方法。 通过将相同频率的两个周期性变化的电磁场施加到预先建立的位置，通过由对象产生的电磁场的独特扰动来确定物体的存在。 施加的电磁场在预先建立的位置中通常是不均匀的，以最大化物体和电磁场之间的相互作用。 拾取线圈用于感测产生的场扰动。 磁力计可以可选地并入感测系统中以抑制由磁性物体产生的错误指示。
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2.发明授权
公开(公告)号：US4249167A
公开(公告)日：1981-02-03
申请号：US45808
申请日：1979-06-05
CPC分类号： G08B13/2408 , G08B13/2448 , G08B13/2471
摘要： Two different frequencies are generated within an interrogation zone. The receiver portion of the system determines the presence of a predetermined marker tag within the interrogation zone by the sensing and processing of a ratio of sideband signals generated by the interaction of the two different frequencies and the predetermined marker tag. The system is greatly immuned to false alarms due to the method of processing the sensed sideband signals. Falsely generated signals are nulled and subtracted out in the receiver portion of the detection system.
摘要翻译： 在询问区内产生两个不同的频率。 系统的接收器部分通过感测和处理由两个不同频率和预定标记标签的相互作用产生的边带信号的比率来确定询问区内预定标记标签的存在。 由于处理感测到的边带信号的方法，该系统被大大地免于假警报。 在检测系统的接收器部分中虚拟产生的信号被零位和减去。
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公开(公告)号：US3990065A
公开(公告)日：1976-11-02
申请号：US551582
申请日：1975-02-20
CPC分类号： G08B13/2408 , G01V3/105 , G08B13/2417 , G08B13/2471 , G08B13/2474 , G08B13/2488
摘要： Apparatus and method for detecting the presence, in an inspection area, of a marker tag having preselected properties. Transfer of articles from a protected area can be monitored by coupling a marker tag with each article and by including an inspection area in all transfer paths. In a theft detection system, the coupled marker tag can be removed or made inoperative in some manner for authorized withdrawal of an article from the protected area.The marker tag is comprised of a small, thin strip of magnetic material. A time-varying magnetic field is provided for interacting with a marker tag located in the inspection area. The magnetic field, which includes components having frequencies f.sub.1 and f.sub.2, has a time-dependent spatial orientation which permits interaction with a marker tag having an arbitrary orientation in the inspection area. The magnetic field components of frequency f.sub.2 produce changes in the magnetic properties of the marker tag, resulting in the generation of a signal having components of frequencies f.sub.1 .+-.2f.sub.2.When the magnitude and phase of the signal having the component f.sub.1 + 2f.sub.2 falls within a range of values of magnitude and phase peculiar to the marker tag, an alarm is activated by signal detection apparatus. The restricted nature of the signals producing an alarm effectively distinguishes a marker tag from signals produced by other objects in the inspection area.
摘要翻译： 用于检测在检查区域中存在具有预选性质的标记标签的装置和方法。 可以通过将标记标签与每个物品联系并通过在所有传送路径中包括检查区域来监控来自受保护区域的物品的传送。 在盗窃检测系统中，耦合的标记标签可以以某种方式被移除或使其不起作用，用于从受保护的区域授权取出物品。
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