Abstract: A ferroelectric memory device includes a plurality of wordlines and a plurality of plate lines, the wordlines and the plate lines being alternately formed at regular intervals in one direction; a plurality of sub bitlines and a plurality of main bitlines, the sub bitlines and the main bitlines alternately formed at regular intervals to cross the wordlines and the plate lines; a plurality of sub cell arrays connected with the wordlines, the sub bitlines and the plate lines, having cells in directions defined by a plurality of rows and columns, the cells in the direction of the rows being arranged every two columns and the cells in the direction of the columns being arranged every two rows, respectively; and switching elements each operating between one of the sub bitlines and one of the main bitlines by an externally applied bitline switch signal of a constant pulse type to selectively connect the sub bitline with the main bitline.

Abstract: A radio frequency amplifier including a long tail pair of transistors provided with a tail current source. The bases of the transistors are driven by emitter follower transistor provided with collector load resistors. Feedback capacitors ensure stability and feedback resistors bias the amplifier without degrading noise performance. The amplifier may be driven unbalanced while retaining good second harmonic distortion performance.

Abstract: A high slew rate operational amplifier circuit of which the through current of its push-pull transistors is substantially zero is disclosed. The operational amplifier circuit preferably comprises an amplifier portion and a push-pull output amplifier including NPN and PNP output transistors. The output of the amplifier portion is transferred to the NPN output transistors base through a PNP driving transistor and to the PNP output transistors base through an NPN driving transistor. The emitters of the driving transistors are connected to respective power supply conductors through respective current sources. The through current reduction is achieved by resistors inserted between the current sources and the corresponding power supply conductors, an NPN transistor so connected with the NPN output transistor as to constitute a current mirror and a PNP transistor so connected with the PNP output transistor as to constitute another current mirror.

Abstract: When an input signal to be amplified is very small and a large blocking signal having a high frequency is included in an input, it is necessary for a filter for mobile communication for removing thereof that a common-mode signal rejection ratio is large. Further, even in the case of an amplifier having a high gain, it is preferable that the common-mode rejection ratio is large in order to avoid saturation of the amplifier by noise. A common-mode rejecting characteristic is added to an input stage by making transconductance circuits of an input of an integrating circuit proposed by Nauta differential circuits and connecting thereof in cross connection. Thereby, a filter as well as an amplifier improving the common-mode rejection ratio of a total, are realized by being applied to a CMOS process or a BiCMOS process.

Abstract: The gain-bandwidth (GBW) limitation problem inherent in all amplifiers is overcome to provide wideband amplifiers with specified characteristics for the transfer function. Parasitic capacitances of transistors are absorbed or incorporated into the design of the passive networks, which are inserted between the gain stages of the amplifier. The component values are determined based on conventional low-pass filter structures. A prototype CMOS transimpedance amplifier implemented using the developed technique achieves over 9 GHz bandwidth and 54 dB transimpedance gain from a 0.5 pF photo-diode capacitance.

Abstract: A resampling technique is used to reduce the noise and improve the signal quality in the output of a prescaler circuit (10). The resampling of the output of a last frequency divider stage is accomplished using at least one flip/flop (FF) (e.g., a D-type FF 18) that is clocked by a signal obtained from the input of the prescaler. This reduces or eliminates the noise caused by edge jitter in the output of the prescaler, as well as the effect of spurious signals generated by the prescaler. These teachings can be used in integer N PLLs and in fractional N PLLs, as well as in single and programmable dual or multi-modulus prescalers. Using this technique the current consumption of the prescaler frequency dividers (12, 14, 16) need not be increased in an effort to reduce the prescaler noise., thereby conserving current in battery powered and other applications.

Abstract: A voltage controlled oscillator comprises an oscillation transistor, a varactor diode, a resonance circuit which is coupled to the oscillation transistor, and a switching diode which changes over a resonance frequency of the resonance circuit, wherein the resonance circuit includes a first strip conductor which is served for grounding a cathode of the varactor diode in terms of direct current and a second strip conductor which is served for coupling a cathode of the varactor diode with the oscillation transistor, the switching diode is connected to the first strip conductor in parallel in terms of high frequency and has a cathode thereof grounded, and a control voltage which is served for changing a capacitive value of the varactor diode is applied to a connection point between the cathode of the varactor diode and the second strip conductor through a choke inductor.

Abstract: Microelectromechanical resonators that can be fabricated on a semiconductor die by processes normally used in fabricating microelectronics (e.g., CMOS) circuits are provided. The resonators comprises at least two vibratable members that are closely spaced relative to a wavelength associated with their vibrating frequency, and driven to vibrate one-half a vibration period out of phase with each other, i.e. to mirror each others motion. Driving the vibratable members as stated leads to destructive interference effects that suppress leakage of acoustic energy from the vibratable members into the die, and improve the Q-factor of the resonator. Vibratable members in the form of vibratable plates that are formed by deep anisotropic etching one or more trenches in the die are disclosed. Embodiments in which two sets of vibratable plates are spaced by ½ the aforementioned wavelength to further suppress acoustic energy leakage, and improve the Q-factor of the resonator are disclosed.

Abstract: The device (1) includes a mixer (4) which generates a signal (S4) having a frequency (F4) equal to the difference between two frequencies (F2, F3), which are those of two signals (S2, S3) each generated by a generator (2, 3) and which vary parabolically as a function of the temperature (T) with quadratic coefficients (&bgr;1,&bgr;2) that are different to each other.

Abstract: A modulator according to the invention includes: a PLL circuit that detects a phase difference between an input signal and a reference signal, an AGC circuit that controls a gain of a modulating signal and outputs a control signal, and a voltage controlled oscillation circuit that controls an oscillation frequency of a signal outputted from the PLL circuit on the basis of the control signal. Here, the voltage controlled oscillation circuit includes: a first voltage controlled reactance unit that inputs the signal outputted from the PLL circuit, a second voltage controlled reactance unit that inputs the control signal, and a high-frequency oscillation circuit connected in parallel with the first and second voltage controlled reactance units, which outputs the input signal. Thereby, the invention achieves to provide a modulator capable of compensating the deviation of the modulation factor, even when the frequency of the carrier signal varies.

Abstract: A method of finding an unknown value from within a range of values is disclosed that divides the range into weighted subranges and then, beginning with an arbitrary search value within the range, performs a number of simple comparisons to determine the value for each subrange that will result in a match with the target value. This method can also detect those cases where the target value lies outside the range. In one embodiment, the method of finding an unknown value within a range of values is applied to impedance matching. In this embodiment, the output impedance of a pin on an integrated circuit is automatically matched to the impedance of the load connected to it. The output driver has a controllable impedance that can be adjusted within a specific range of impedances to match the external load impedance it is to drive.

Abstract: A novel junction design was developed for use with in-line combiner networks to minimize electrical length between the resonators being combined and to optimize coupling. It consists of a combiner comprising a plurality of cavity resonators coupled to a combining mechanism. The combining mechanism is placed outside of each resonator a prescribed distance above the ground plane. Combiner pairs are created by connecting two cavities to each other using quarter-wave lines. The central combiner pair is directly connected to the output connector through a common port. The quarter-wave junctions not directly connected to the output connector are then connected to the output port through half-wavelength lines. Iris or aperture coupling is controlled by a sliding cover that is adjusted using a free-rotating screw and is secured with locking screws to ensure good electrical and RF grounding.

Abstract: A small high frequency circuit component has very small variations in stray capacitance generated between an inductor electrode pattern and a capacitor electrode pattern. As a result, the variations in the characteristics thereof are also small. The inductor electrode pattern is overlaid with the capacitor electrode pattern in a plan view. That is, when viewed from the lamination direction, the projection of the inductor electrode pattern onto the capacitor electrode pattern is included within the capacitor electrode pattern.

Abstract: There are provided a resonator for use in a filter, which interprets and reduces intermodulation distortion by analyzing characteristics of current density occurring at resonance and linear and nonlinear characteristics of the filter, a method for manufacturing filters by using the resonator and a filter manufactured by the method. The resonator has a ratio of an inside diameter to an outside diameter belonging to a range which is larger than about 1:3 and smaller than or equal to about 1:3.75 and its length (H) is about &lgr;/4, wherein &lgr; is a wavelength of a plane wave provided to the resonator. By employing the method, it is possible to effectively design the filters through the use of a circuitry and structural approach with breaking from a conventional approach depending on local and minute processing steps when manufacturing the filters.

Abstract: A tunable electrical filter constructed pursuant to the teachings of the present invention includes: (a) a plurality of resonator units coupled between an input locus and an output locus; and (b) a plurality of tunable dielectric varactor units; respective individual varactor units of the plurality of varactor units being coupled between respective pairs of the plurality of resonator units, coupled between the plurality of resonator units and the input locus, and coupled between the plurality of resonator units and the output locus.

Abstract: A small in-band-flat-group-delay type dielectric filter having low-loss characteristics with a small amplitude deviation and uniform-group-delay frequency characteristics is obtained, which enables broad-band characteristics to be obtained easily. The in-band-flat-group-delay type dielectric filter includes a plurality of dielectric coaxial resonators, a coupling circuit comprising a combination of reactive elements, with which the dielectric coaxial resonators are coupled to one another, and input/output terminals connected to ends of the coupling circuit. The dielectric coaxial resonators coupled to the input/output terminals are allowed to have a different characteristic impedance from that of the inter-stage dielectric coaxial resonators.

Abstract: The present invention provides a small, thin filter circuit showing a desired filter characteristic which is highly accurate, and producible with a high efficiency. The filter circuit includes a pair of dielectric insulating layers 2 and 3, upper and lower, each having a ground pattern 11 (16) formed on the main side thereof, and an inner wiring layer 4 formed between the dielectric insulating layers 2 and 3 and having capacitively coupled resonator conductive patterns 6 and 7 each connected at one end thereof to the ground patterns 11 and 16 via inter-layer connecting vias 12 and open-circuited at the other end.

Abstract: In a dielectric block, an array of three excitation holes, in each of which one opening is a short-circuited end and the other opening is an open-circuited end, are disposed so as to be interdigitally coupled and balanced input-output terminals are provided at the opening of the excitation holes at both ends of the array. A resonator hole is provided so as to be coupled to one excitation hole of the excitation holes at either end of the array. Thus, a compact dielectric filter with balanced input-output terminals is constructed.

Abstract: A dielectric filter includes a dielectric block having inner-conductor-formed holes extending from a first face of the dielectric block to a second face opposed to the first face. Inner conductors are formed inside the inner-conductor-formed holes such that both ends of the inner-conductor-formed holes are open-circuited. On the exterior surface of the dielectric block, balanced input/output terminals are capacitively coupled to the open ends of the inner-conductor-formed holes. A metal cover is provided so as to cover one of the first or second face of the dielectric block. The metal cover functions as a short-circuit conductor in a spurious mode such as a TE mode other than a TEM mode, and hence the influence of the spurious mode is avoided.

Abstract: A coaxial connection is electromagnetically shielded at an interface between a surface mountable coaxial connector and a planar circuit operating in the radio frequency (RF) and microwave frequency ranges. In addition or alternatively, the coaxial connection reduces a potential impedance mismatch associated with attaching a coaxial transmission line of the coaxial connector to a planar transmission line of the planar circuit.

Abstract: The aim of the invention is to protect an electromagnetic switching device when a load (6) is switched to a supply voltage (U). A current (IL) that flows through the load contact (2) is monitored. The electric circuit is interrupted when the current (IL) exceeds a threshold value that is below the current carrying capacity of the load contact (2). The electric circuit is automatically closed again after the current (IL) which flows through the load contact (2) has decreased.

Abstract: In an artificial magnetic conductor, the distance between the frequency selective surface and the ground plane is mechanically varied to adjust the effective inductance or capacitance of the structure and thus the resonant frequency of the device.

Abstract: A circuit breaker for interrupting the flow of current upon the detection of excess current or temperature is provided that has a current conducting blade mounted on a blade cross bar, which has a blade biasing spring for urging the blade to a first pivotal position on the blade cross bar during the open, closed, and tripped operation of the breaker, and for latching the blade in a second pivotal position on the blade cross bar upon the occurrence of a blown-open action of the breaker. The spring is a torsion spring that is coiled around a spring mounting pin, having a first end leg extending outwardly and formed into a hook anchored in a hook accommodating opening, and having a second end leg extending outwardly and cantilevered in contact with a spring follower pin. The second end of this leg is bent away from the spring follower pin to reduce the spring force exerted between the blade cross bar and the blade upon the occurrence of a blow-open action of the circuit breaker.

Abstract: An electromagnetic relay is provided with an iron core (50) which has a virtually J-letter shape on a plan view with one end serving as a support-receiving portion (51) and the other end serving as a magnetic pole portion (52), and a movable iron member (60) which is supported by a movable contact member (70) attached to a corner thereof, and has a virtually L-letter shape on a plan view with one end (61) being supported on the support-receiving portion (51) of the iron core (50) so as to freely pivot thereon and an adsorb portion (62) that is the other end being allowed to face the magnetic pole portion (52) of the iron core (50) so as to be adsorbed thereon. The objective of the present invention is to provide an inexpensive electromagnetic relay which is less susceptible to deviations in the adsorb portion of the movable iron member that comes into contact with and separates from the magnetic pole portion of the iron core, and has stable operation characteristics.

Abstract: An electromagnetically actuable device includes a base. A magnetic core is fixedly mounted to the base. An armature is movably mounted to the base proximate the magnetic core. A coil is fixedly mounted to the base and is selectively energized to draw the armature to the magnetic core. The armature and magnetic core have mating surfaces adapted to provide three contact areas in a triangular configuration to provide minimal magnetic air gap and a stable interface when the coil is energized.

Abstract: An electromagnetically actuable device has a magnetic core proximate an armature and a coil selectively energized to draw the armature to the magnetic core. The armature and magnetic core are of laminated magnetic steel and have mating surfaces. At least one of the armature and magnetic core includes conductive weld or braze lines for integrally securing laminations together to define a conductive path proximate the mating surface to provide a shading coil.

Abstract: A circuit breaker comprising a fixed contact; a moveable contact, which is moveable into and out of electrically conductive engagement with said fixed contact; a line terminal operatively coupling said fixed contact with a circuit to be protected by said circuit breaker; a middle terminal operatively coupling said moveable contact with said circuit to be protected, in series with said line terminal, said fixed contact and said moveable contact; and a load terminal in series with said middle terminal and operatively coupling said circuit breaker to a load, a trip mechanism responsive to at least a thermal trip element for causing the moveable contact to move out of engagement with the fixed contact in response to a given amount of thermal energy caused by current over time passing through a circuit breaker current path comprising said fixed contact, said movable contact, said line terminal, said middle terminal, said load terminal and said thermal trip element from a circuit to be protected, wherein at least o

Abstract: A control method for an electromagnetic actuator for the control of a valve of an engine from an abutment condition, in which an actuator body actuating the valve and disposed to move between two electromagnets is maintained in abutment against a first excited electromagnet and against the action of at least one elastic body; in order to bring the actuator body into abutment against a second electromagnet, the first electromagnet is de-excited and the second electromagnet is then excited by means of excitation parameters, which are determined as a function of the measurement of the mean value of the disturbance force acting on the valve during the stage of de-excitation of the first electromagnet.

Abstract: A noncontact transformer installed on the floor of a housing whereby air entrapment within the resin that fills spaces in the transformer is prevented. A primary transformer component is provided on a lower surface of a primary housing, which is then filled with resin. Primary transformer component includes a core space which is defined by inclined internal wall that extends away from the lower surface to form a widely open end of the core space that is larger than the end at the lower surface.

Abstract: An inductance component comprising a column-shaped magnetic material substrate 21, conductor layer 24 covering ends and a peripheral surface of the substrate, coil portion 27 having groove portion 25 and wire conductor portion 26 formed in the conductor layer covering the peripheral surface, electrode portions 28 including the conductor layer covering the ends of the substrate, and magnetic material portion 31 made of sintered magnetic material on the coil portion, wherein the conductor layer has a melting point higher than a sintering temperature of the sintered magnetic material. The manufacturing process comprises; forming a substrate, forming a conductor layer, forming a coil portion, forming electrode portions at ends of the substrate, and forming a magnetic material portion of sintered magnetic material on the coil portion. The present invention provides an inductance component with high inductance, low magnetic flux leakage, and less bad magnetic effects to adjacent components.

Abstract: A common-mode choke coil includes first to third spiral coils, in which the diameters of coil portions are substantially the same and the axes of the coil portions are aligned collinearly. Extended portions of the first and second coils have a flectional pattern and connect coil portions located at substantially the center in the longitudinal direction of sheets and input/output electrodes. The junctions of the extended portions and the coil portions have a folded configuration. Accordingly, the number of turns and the line length of the first coil are the same as those of the second coil.

Abstract: A coil for electrical and electronic equipment comprises a spiral conductor coil 2 prepared by disposing coaxially a plurality of conductors 4a through 4d each having a flat circular arc-shaped configuration in multiple stages along a vertical direction, and linking sequentially ends of these conductors 4a through 4d to each other by means of linking members 5a through 5c in the vertical direction; and an insulating layer 3 covering the surface of the conductor coil 2, so that a relationship between a conductor width and a coil core diameter does not depend mutually, it becomes possible to increase and decrease optionally the conductor width and the coil core diameter, and as a result, a wider conductor width and a smaller coil core diameter in the conductor coil 2 than that of a conventional coil can be achieved.

Abstract: An access control system is provided wherein identification data such as a photograph is downloaded from a trusted authority to a security system. Security personnel can then compare the person seeking access to an image of the person as sent by the trusted authority, and avoid reliance on identification documents presented by the person seeking access.

Abstract: A pager transceiver and method for selectively paging provides a page to a paging transceiver but does not automatically provide associated information. The paging transceiver receives the page and alerts the user that information is waiting and preferably provides a short description of the information. The user can then download or otherwise act on the information at a time and at a place convenient to the user. The user can therefore place the paging transceiver in a location where it can easily receive and reply to the message. The paging system conserves air time and the paging transceiver conserves memory by not automatically receiving the associated messages. The messages stored by the systems and delivered to the paging transceiver may be of different types, such as voice, text, audio, or even video. In addition to messages, the paging system can store other information for the user, such as songs or video clips that the user can sample or updates on weather or stock rates.

Abstract: An electric power line communication system operates with an electric power distribution system to provide through premises power distribution lines highly reliable communication links among receiving devices electrically coupled or located in proximity to the premises power distribution lines. A power line transceiver is designed to transmit and receive through the premises power distribution lines modulated carrier signals conveying information over the communication links. The power line transceiver operates in a transmitter mode as an intentional radiator to emit modulated carrier signals by transmitting them at a frequency band and a power level sufficient to form by electrical conduction a communication link with a modulated carrier signal receiving device.

Abstract: A supply line structure for the energy supply of electrical components of a motor vehicle, and for transmitting information between at least a portion of the components. To reduce the interference susceptibility of the supply line structure in a Powerline Communications, and at the same time to continue to be able to ensure the energy supply of the electrical components via the supply line structure, it is provided that the supply line structure have separate supply lines, electrically isolated from the vehicle body, as return lines from the components to at least one energy source of the motor vehicle. The supply lines of the supply line structure preferably take the form of coaxial lines or twisted pair lines.

Abstract: An indicator for use with a microphone of a vehicular audio system, such as a cellular telephone, emergency communication device, or other audio device, provides a user of the audio system with a status signal relating to a reception quality of a vocal signal from the user. The microphone may be mounted within an accessory module, which may be mounted to an interior surface of a vehicle windshield. The accessory module houses a microphone and may be positioned adjacent to a headliner of the vehicle generally above an interior rearview mirror which is supported therebelow. The accessory module provides a fixed orientation of the microphone and is easily installed to the vehicle as it is manufactured or as an aftermarket device. The accessory module may further include a wire cover, which extends to a mounting for the mirror in order to substantially encase a mirror wire harness, thereby retaining the mirror harness and providing a finished appearance to the mirror and accessory module.

Abstract: A warning device for mounting onto a vehicle, in order to attract the attention of the driver when another vehicle (2) or object is located in a position that is wholly or partially critical for the driver. The device comprises two sources (5, 6) of laser radiation arranged at a distance from each other, a convex lens (8) arranged outside of each source and a position-sensitive radiation detector (7) arranged between the sources (5, 6). The device reacts with different levels of warning signals on the detection of direction indicator (58), angular deviation (60) of a wheel or the steering wheel, speed (62), etc., in combination.

Abstract: The invention relates to a method for detecting a drop in pressure of a motor vehicle tire by evaluating wheel speeds determined by sensors. The method for detecting the drop in pressure is based on the detection of a large drop in pressure or a complete drop in pressure using a reduction of the angular velocity or an increase (8) in the dynamic read radius rd of one or more wheels. The invention also relates to a device for controlling the braking power and/or driving dynamics and for measuring the pressure of vehicle tires wherein a microcomputer, which is connected to wheel rotational speed sensors and optionally to driving dynamic sensors, is used to perform the aforementioned method and a known method for regulating the braking power and/or driving dynamics.

Abstract: A system and method of identifying and removing artifact from radio frequency noise from biopotentials identifies epochs contaminated with radio frequency noise. Contaminated epochs are then replaced with recent uncontaminated epochs stored in a buffer, depending on the current level of artifact and the availability of suitable data. Discontinuities arising at the beginning of the replaced epochs are smoothed by means of a windowing function.

Abstract: An asset, object, person or animal monitoring system and associated method for monitoring assets, objects, people or animals utilizing impulse radio techniques. The asset, object, person or animal monitoring system of the present invention can vary the duty cycles of the impulse radio transmitters, by both manual and automatic means, to adapt to varied requirements.

Abstract: The present invention describes the use of a space-based Extremely Low Frequency (ELF) magnetic field detector in conjunction with ground-based network of ELF magnetic field detectors. In particular, a space based ELF detection system can be used to perform a wide area search and find precursor earthquake signals in both known and unknown earthquake zones, and a ground-based network of ELF detectors can be used to verify that the signals are indeed earthquake generated signals. The use of this invention will minimize cost and manpower necessary to effectuate an accurate and reliable earthquake detection system.

Abstract: An automated, flexible and programmable system to update delivery and inventory status for an aggregate of remote mailboxes, bins, shelves, sorter bins, and/or a plurality of bins to distant customers and vendors through email, pager, personal digital assistant (PDA), cellular phone mail, voice mail at call centers and/or web site mailboxes. It can function as a delivery notice to mailbox recipients or as inventory stock management to store owners and vendors at remote locations. Various sensors mounted on flexible circuit boards located on the mailboxes, bins, or shelves together with distributed microcontrollers report status through a common bus to a master controller and then to a computer system. The computer in turn dispatches reports and information to various owners and vendors via a remote network operation center accessed through a dedicated line, a wireless service or an Internet Service Provider.

Abstract: An aircraft cockpit door system is disclosed comprising a bulletproof cockpit door and bulkhead, and a bulletproof lavatory isolation door and bulkhead. A logic control circuit alternately locks the two doors, keeping the cockpit crew at all times isolated from other persons aboard the craft to ensure the safety of the cockpit crew, and ultimately the aircraft.

Abstract: A tamper resistant magnetic contact switch apparatus for alarm systems that has a plurality of magnetic reed switches configured in a logic circuit and a magnetic pack for actuation. A magnetic shield disposed around the switches defines an actuation zone. In combination with the magnetic shield preventing magnetic fields from reaching the switches from locations outside the actuation zone, the magnet pack activates two of the five switches when positioned within the actuation zone to complete the logic circuit. The magnet pack does not, however, activate any of the other switches. If any of the other three switches are activated, or if either of the two activated switches are deactivated, the logic circuit is broken and the alarm circuit is activated.

Abstract: An anti-thief security sensor assembly wherein the alignment of the respective optical axes of the beam projecting unit and receiving unit with each other can be performed continuously over a required length of time is provided which includes a beam projecting unit (1) for emitting an infrared beam (IR), and a beam receiving unit (2) for receiving the infrared beam (IR) emitted from the beam projecting unit (1). The beam projecting unit (1) includes a first switch (16) adapted to be activated when a cover (10) protecting the beam projecting unit (1) is removed and for outputting a discriminative signal (B) descriptive of removal of such cover, and a transmitting circuit (17) for transmitting the discriminative signal (B) from the beam projecting unit (1) to the beam receiving unit (2), and a recognizing circuit (28) for receiving the discriminative signal (B) and outputting a notifying signal necessary to generate an alarm indicative of the removal of the cover (10).

Abstract: Tamper detection and prevention for an object control and tracking system and particularly a Key Track system is provided. Where objects being tracked are keys, a key card having a touch memory device, RF id tag, or other circuitry for storing and transmitting an ID to a controller is provided. A tether attaches a key to the card. In one embodiment, the tether is conductive and the transmission of the ID code passes through the tether. If the tether is cut, transmission is interrupted to indicate a tampering condition. In another embodiment, the tether is resistive and circuitry is provided to monitor a voltage drop across the tether. A change in the voltage drop indicates a tampering condition. An object of the invention is to detect an attempt to remove the key (or other object) from its ID card while leaving the card intact.

Abstract: An RFID antenna system for providing an interrogation zone over a width of a dock bay door comprises a horizontally arranged array of antennas, each of the antennas being substantially coplanar with all of the other antenna(s), and a circuit operatively coupled to the array for providing a respective signal to each of the antennas to enable each of the antennas to emit an interrogation field. The interrogation fields emitted from the respective antennas jointly form an interrogation zone in a volume positioned above each of the antennas. Each of the antennas is mounted on, within or beneath a portion of the floor which is close to the dock bay door.

Abstract: A seal includes a first housing member defining a recess and detent structure and a tail having an end thereof secured with the first housing member and extending outwardly of the first housing member, the tail having a securement structure at a free end thereof, the tail securement structure being receivable in the detent structure, an EAS marker disposed in the recess and a second housing member having a compartment therein for retentively containing the first housing member.

Abstract: A miniature resonating marker assembly that includes, in one embodiment, a ferromagnetic core, a wire coil disposed around the core, and a capacitor connected to the wire coil adjacent to the magnetic core. The core, coil, and capacitor form a signal element that, when energized, generates a magnetic field at a selected resonant frequency. The magnetic field has a magnetic center point positioned along at least one axis of the signal element. An inert encapsulation member encapsulates the signal element therein and defines a geometric shape of the resonating marker assembly. The geometric shape has a geometric center point substantially coincident with the magnetic center point along at least a first axis of the signal element. The shape and configuration of the assembly also provides for a miniature signal element specifically tuned to resonate at a selected frequency with a high quality factor.