Electronic article security system with digital signal processing and increased detection range
First Claim
1. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, wherein the transmitter means comprises:
- a controlled oscillator for receiving control signals from the data processing and control means and for generating electromagnetic output signals which vary in frequency over a predetermined frequency range at a predetermined rate as established by the control signals;
driver means for receiving the oscillator output signals and for sending the oscillator output signals along a predetermined transmission path;
transmission path receiver means connectable to the transmission path for receiving the oscillator output signals; and
amplifier means connected to the transmission path receiver means for receiving and amplifying the oscillator output signals to provide the electromagnetic energy emitted by the antenna means.
3 Assignments
0 Petitions
Accused Products
Abstract
An improved electronic article security system is employed for detecting the presence of a security tag within a detection zone. The system includes a transmitter for generating electromagnetic energy and, in the disclosed embodiment, a single antenna for emitting electromagnetic energy received from the transmitter to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone. A receiver is provided for processing signals from the antenna relating to sensed disturbances and for providing output signals. A data processing and control section analyzes the output signals from the receiver and determines whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone. The output signals from the receiver are analyzed in accordance with predetermined criteria and pattern recognition techniques based upon receiver output signals which would be expected if a security tag were present in the detection zone to establish a security tag probability percentage.
192 Citations
101 Claims
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1. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, wherein the transmitter means comprises:
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a controlled oscillator for receiving control signals from the data processing and control means and for generating electromagnetic output signals which vary in frequency over a predetermined frequency range at a predetermined rate as established by the control signals; driver means for receiving the oscillator output signals and for sending the oscillator output signals along a predetermined transmission path; transmission path receiver means connectable to the transmission path for receiving the oscillator output signals; and amplifier means connected to the transmission path receiver means for receiving and amplifying the oscillator output signals to provide the electromagnetic energy emitted by the antenna means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, wherein the receiver means comprises:
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a first balanced mixer for receiving and mixing together signals from the antenna means and signals from the transmitter means to establish first detected signals; a second balanced mixer for receiving and mixing together signals from the antenna means and phase shifted signals from the transmitter means to establish second detected signals which are out of phase with respect to the first detected signals; and a sum/difference circuit for receiving the first and second detected signals from the mixers and, in a controlled manner, obtaining either the sum of or the difference between the detected signals. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone. receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising:
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a first filter for performing shorter term filter averaging of output signals from the receiver means; a second filter for performing longer term filter averaging of output signals from the receiver; and subtraction means for subtracting the results of the second filter from the results of the first filter to provide resultant signals with reduced random or transient noise, reduced correlated or environmental noise and enhanced signal to noise ratios. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising:
means for analyzing the output signals from the receiver in accordance with predetermined criteria and pattern recognition techniques based upon receiver output signals which would be expected if a security tag were present in the detection zone and for establishing for the receiver output signals a security tag probability percentage. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59)
- 60. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection. Zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising verification means for verifying the physical presence of an object within the detection zone independently of the detection of a security tag.
- 75. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising input/output means for direct access to the data processing and control means to permit programming, reprogramming, monitoring, testing or adjusting of the data processing and control means.
- 84. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising auto tune means for automatically adjusting data processing parameters to compensate for local environmental and system operational factors for enhancing the ability of the system to determine whether sensed disturbances are caused by a security tag.
- 89. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising means for determining the direction of movement of a person who passes through the detection zone.
- 96. In an electronic article security (EAS) system for detecting the presence of a security tag within a detection zone, transmitter means for generating electromagnetic energy, antenna means for emitting electromagnetic energy received from the transmitter means to establish an electromagnetic field within the detection zone and for sensing disturbances within the electromagnetic field, including disturbances resulting from a security tag within the detection zone, receiver means for processing signals from the antenna means relating to sensed disturbances and for providing output signals, and data processing and control means for analyzing the output signals from the receiver means and for determining whether a sensed disturbance within the electromagnetic field is caused by the presence of a security tag within the detection zone, the data processing and control means comprising means for communicating with other EAS systems to establish a multiple system network wherein the first EAS system in the network to determine that a sensed disturbance is caused by a security tag generates a deactivating signal to the other EAS systems in the network.
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98. A hi-directional infrared communication system comprising:
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a first infrared transmitter means located on a first side of an area for transmitting a first infrared beam through the area in a first direction; a second infrared transmitter means located on a second side of the area for transmitting a second infrared beam through the area in a second direction generally opposite the first direction, the first and second infrared beams being generally parallel and spaced apart a predetermined distance, the first and second infrared beams being separately distinguishable from each other; a first infrared receiver means located on the second side of the area and generally aligned with the first infrared transmitter means for receiving the first infrared beam and for generating first output signals; and a second infrared receiver means located on the first side of the area and generally aligned with the second infrared transmitter means for receiving the second infrared beam and for generating second output signals, the first and second receiver means including detection means for determining which infrared beam is being received. - View Dependent Claims (99, 100, 101)
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Specification