Abstract: A multi-frequency RFID remote communication system is provided that includes a plurality of RFID tags configured to receive a first signal and to return a second signal, the second signal having a first frequency component and a second frequency component, the second frequency component including data unique to each remote RFID tag. The system further includes a reader configured to transmit an interrogation signal and to receive remote signals from the tags. A first signal processor, preferably a mixer, removes an intermediate frequency component from the received signal, and a second processor, preferably a second mixer, analyzes the IF frequency component to output data that is unique to each remote tag.

Abstract: Devices having either wireless data communication capability or RFID tags can be located using dual function fixed devices which are distributed throughout a facility. The devices will identify those units with which they are communicating using a wireless radio data communications protocol and also identify items within the local area using RFID tags on the units.

Abstract: A device for reducing radiation from an antenna of a portable telephone, includes a main body having an outer body with a central bore, and an antenna gripping member mounted in the bore and having an antenna receiving opening for receiving the antenna of the telephone; a radiation reducing lead shield mounted to an outer surface of the main body and extending only partially therearound for reducing electromagnetic radiation from the antenna to a person using the telephone; a cover body in surrounding relation to the main body and the radiation reducing shield, and including a cover opening in alignment with the antenna receiving opening; and indicia on the cover body for indicating an orientation of the main body on the antenna such that the radiation reducing shield is positioned on a side of the antenna which is opposite from the earpiece speaker.

Abstract: Disclosed is a wireless telecommunication terminal constructed with a housing in which a transmitter/receiver module is received; an earpiece is disposed at the upper portion of the front face of the housing; a liquid crystal display is disposed below the earpiece; a keypad having a plurality of keys and functional buttons is disposed below the liquid crystal display; a cover is rotatably hinge-coupled to the housing; and an antenna established either on the surface of the cover or inside of the cover. The antenna is preferably constructed as either a plane monopole antenna, a plane dipole antenna, a slot antenna, a reverse F antenna, a reverse L antenna, or a micro-strip antenna.

Abstract: The present invention relates to a proximity IC card (PICC). More particularly, the present invention relates to and provides a detection circuit of a simple structure, which is easy to set up in a PICC and a proximity coupling device (PCD) for transmitting data to and receiving data from the PICC. This detection circuit is operative to detect a subcarrier signal sent from a PICC and superposed onto a carrier signal received through an antenna. Further, this detection circuit comprises a bias circuit for applying predetermined DC potential to a signal received from the antenna, a rectifier circuit for extracting a subcarrier signal superposed onto the carrier signal by rectifying a signal received from the antenna at a bias point, and an amplifier circuit for amplifying the subcarrier signal extracted at the bias point.

Abstract: Apparatus, and an associated method, for forming a space-generated multilevel coding scheme for a radio communication system. Two or more modulators are positioned at a sending station. The modulators modulate, pursuant to separate modulation schemes, data that is to be communicated by the sending station. The modulation schemes are lower-order modulation schemes. The modulated data is communicated to a receiving station, and detected at a least single receive antenna. The modulated symbols formed by the separate modulators are superimposed theretogether and form symbols of a higher order modulation scheme.

Abstract: The present invention includes backscatter communication systems, interrogators, methods of communicating in a backscatter system, and backscatter communication methods. According to one aspect of the present invention, a backscatter communication system includes an interrogator including a transmitter configured to output a forward link communication and a receiver configured to receive a return link communication having a carrier signal, the receiver being configured to reduce the amplitude of the carrier signal of the return link communication; and a communication device configured to modulate the carrier signal to communicate the return link communication responsive to reception of the forward link communication.

Abstract: An inductive reader device (104) communicates with a transponder (102) using electromagnetic coupling. The reader device includes a transmitter (112), a receiver (114), a first coil element (116), and a second coil element (118). The first coil element is directly connected to the transmitter to emit a radio frequency excitation signal. The first coil element receives a radio frequency response signal from the transponder via electromagnetic coupling. The second coil element is directly connected to the receiver to provide a response signal to the receiver. The second coil element is loosely or inductively coupled to the first coil element via a predetermined mutual inductance due to the spatial relationship between the first coil element and the second coil element. Hence, the second coil element receives the radio frequency response signal from the first coil element. Advantageously, a signal coupler required for the receiver is integrated with an antenna element by virtue of the second coil element.

Abstract: An enhanced backscatter RF-ID tag reader system and multiprotocol RF tag reader system is provided. In a multiprotocol mode, the system emits a non-stationary interrogation signal, and decodes a phase modulated backscatter signal by detecting a stronger phase component from quadrature phase representations or determining phase transition edges in a phase of a received signal. The RF tag reader system predicts or follows the phase of the backscatter signal, thereby avoiding interference from nulls in the received signal waveform due to the non-stationary interrogation signal, relative movement or environmental effects. An acoustic RF-ID tag detection system detects the reradiated signal corresponding to respective transformation of a signal in the tag. Detection of either type of RF-ID tags therefore is possible, and the absence of any tag or absence of any valid tag also determined.

Abstract: A data communication apparatus according to the present invention can be used both in one-wave mode and two-wave mode, and includes: first and second tuning circuits (1, 2); a power supply circuit (3) connected to first tuning circuit (1) for generating power by a signal received by first tuning circuit (1); an information processing circuit (15) connected to first tuning circuit (1) or second tuning circuit (2) through a switching circuit (6) and including a detection circuit (7), a decoder (8), an encoder (10) and the like. Information processing circuit (15) includes a switch control circuit (14) detecting if the mode of the received radio wave is one-wave mode or two-wave mode in accordance with an output from first tuning circuit (1) and controlling switching circuit (6) such that detection circuit (7) is connected to one of first and second tuning circuits (1, 2).

Abstract: In accordance with the present invention, a duplex radio communication system comprises an Interrogator which generates a radio signal to at least one remote Tag. The remote Tag receives the radio signal. The Tag then generates a subcarrier signal, and using Quadrature Phase Shift Keying (QPSK), modulates an information signal onto the subcarrier. A Backscatter Modulator, using this modulated subcarrier, modulates the reflection of the radio signal, the reflected signal being a reflected modulated signal. The Interrogator receives and demodulates the reflected modulated signal to obtain the information signal. In one embodiment, demodulation utilizes a homodyne detector. In another embodiment, the Interrogator modulates an information signal onto the radio signal, transmits that modulated radio signal to the Tag, and the Tag demodulates that modulated radio signal to recover the information signal.

Abstract: A long-range communications apparatus utilizing modulated-reflector technology is described. The apparatus includes an energy-transmitting base station and remote units that do not emit radiation in order to communicate with the base station since modulated-reflector technology is used whereby information is attached to an RF carrier wave originating from the base station which is reflected by the remote unit back to the base station. Since the remote unit does not emit radiation, only a low-power power source is required for its operation. Information from the base station is transmitted to the remote unit using a transmitter and receiver, respectively. The range of such a communications system is determined by the properties of a modulated-reflector half-duplex link.

Abstract: A communication station (1) for contactless communication with at least one transponder is provided with a transmission coil configuration (2) with an active, first transmission coil circuit (21) which includes a first transmission coil (36) and with a passive, second transmission coil circuit (22) which includes a second transmission coil (42), the first transmission coil (36) as well as the second transmission coil (42) being connected to a respective central conductor (38, 50) which is connected, via a third capacitor stage (41, 53), to a connection conductor (33, 48) between two series-connected capacitor stages (31, 32 and 47, 49), the two capacitor stages (31, 32 and 47, 49) constituting capacitor means (30, 43) which are connected parallel to the relevant transmission coil (36, 42).

Abstract: Cell Phone Shield with a foam padded ear piece, a double hinge mechanism attached to one side of the ear piece, a stationary flat panel attached to the hinge along one edge, a double sided adhesive panel attached to the stationary flat panel, the double sided adhesive attaching the flat panel to the reverse side of a cell phone corresponding to the location of the cell phones ear resting location, the double hinge having resilient members built in to cause said padded ear piece to remain in place whether in the storage position or the use position, and said double hinge having a floating post member to allow said ear piece to float outwards to accomodate cell phones of different thicknesses.

Abstract: A reflector circuit is provided which responds to illuminating radiation with corresponding output radiation of increased magnitude relative to the illuminating radiation. The circuit comprises an antenna for receiving the illuminating radiation and emitting corresponding output radiation, a delay line providing a frequency selective limiting and signal storage characteristic and an amplifier assembly incorporating a reflection amplifier for providing signal amplification. The reflection amplifier is capable of providing high gains approaching +30 dB at relatively low current consumption, for example, tens of microamperes. The antenna provides an input signal upon receipt of the illuminating radiation, a portion of which is amplified, frequency selectively filtered, and then stored for a period after which it is emitted as the output radiation from the circuit. Switches may be incorporated and are operable to counteract spontaneous oscillation within the circuit.

Abstract: The present invention comprises a power transmission system, an IC card, and an information communication system using an IC card. In the power transmission system, power is transmitted by radio from the power transmission device to the IC card. In the IC card, the transmitted induced power is converted into a DC voltage, the transmitted induced power or a voltage corresponding to the induced power is detected, and a desired DC voltage to be suppled to the internal circuit is obtained in controlling resistance the detected induced power or the voltage corresponding to the induced power.

Abstract: An interrogator for use in a backscatter system, the interrogator comprising an antenna configured to receive a backscatter signal; an IQ downconverter coupled to the antenna and configured to downconvert the backscatter signal to produce I and Q signals; a combiner coupled to the IQ downconverter and configured to combine the I and Q signals to produce a combined signal; and an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal. A method of communications in a backscatter system, the method comprising receiving a backscatter signal; downconverting the backscatter signal with an IQ downconverter to produce I and Q signals; combining the I and Q signals to produce a combined signal; and converting the combined signal to a digital signal.

Abstract: A communication station (1) for contactless communication with at least one transponder is provided with a transmission coil configuration (2) with an active, first transmission coil circuit (3) which includes a first transmission coil (4) and with a passive, second transmission coil circuit (7) which includes a second transmission coil (8), and additionally with an active, third transmission coil circuit (11) which includes a third transmission coil (12); in a preferred embodiment a coupling coil (15) is coupled to the second transmission coil (8), first receiving means (32) being connected to the first transmission coil circuit (3) and to the third transmission coil circuit (11) whereas second receiving means (37) are connected to the coupling coil (15), both receiving means (32, 37) delivering received data (RDA) which can be applied to data evaluation means (19).

Abstract: The present invention includes backscatter communication systems, interrogators, methods of communicating in a backscatter system, and backscatter communication methods. According to one aspect of the present invention, a backscatter communication system includes an interrogator including a transmitter configured to output a forward link communication and a receiver configured to receive a return link communication having a carrier signal, the receiver being configured to reduce the amplitude of the carrier signal of the return link communication; and a communication device configured to modulate the carrier signal to communicate the return link communication responsive to reception of the forward link communication.

Abstract: An apparatus for controlling the whereabouts of an animal is affixed to the animal and selectively administers appropriate aversive stimuli effective to deter the animal from encroachment of boundaries in accordance with predetermined conditions based on the coding and/or timing of radio signals received from at least one transmitter, which may include a wire loop. The apparatus receives radio signals intermittently transmitted from the transmitters, wherein the radio signals define at least one boundary for the animal. The apparatus then selectively administers the appropriate aversive stimuli in response to determining that at least one of the received radio signals satisfies one or more of the predetermined conditions.

Abstract: An interrogator for use in a backscatter system, the interrogator comprising an antenna configured to receive a backscatter signal; an IQ downconverter coupled to the antenna and configured to downconvert the backscatter signal to produce I and Q signals; a combiner coupled to the IQ downconverter and configured to combine the I and Q signals to produce a combined signal; and an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal. A method of communications in a backscatter system, the method comprising receiving a backscatter signal; downconverting the backscatter signal with an IQ downconverter to produce I and Q signals; combining the I and Q signals to produce a combined signal; and converting the combined signal to a digital signal.

Abstract: An RF signaling system and system for controlling the whereabouts of animals utilizing same functions, in a preferred embodiment, by efficiently establishing well-defined electronic boundaries using small, battery powered transmitters transmitting constant envelope RF signals in a near-field regime by repetitively delivering trains of brief, low duty cycle pulses of electrical energy to a resonant circuit which includes an antenna at a low RF carrier frequency corresponding to the resonant frequency of the circuit. During intervals between pulses, the resonant circuit is effectively isolated from the circuit delivering the pulses to minimize loading effects. Further energy efficiency is achieved by interposing inactive interals between at least some successive transmissions of the RF signals represented by the pulse trains. The RF signals emitted by the transmitters are digitally encoded as are those emitted from a wire loop coupled to an optional wire loop unit to define a wire loop boundary.

Abstract: Apparatus and method for reducing the interference of digital cellular telephones with hearing aids. A digital cellular phone is provided with a second antenna that transmits a local, low-power signal which fills in the gaps in the transmitted switched information carrier. This prevents the hearing aid from demodulating the low frequency switched carrier components of the digital cellular phone. Alternatively, the main antenna can transmit on a garbage frequency between time slots, or the hearing aid can detect and cancel the interfering signal.

Abstract: A tuner part of a digital satellite broadcasting receiver includes an IF signal demodulator part and an I/Q signal demodulator part. These demodulator parts are formed on different substrates, and covered with different chassis respectively. Low-pass filters are provided between an amplifier circuit of the IF signal demodulator part and an output terminal and between an IF signal input terminal of the I/Q signal demodulator part and a baseband converter circuit respectively. Further, an AGC detector circuit for detecting the level of an IF signal for the baseband converter circuit is provided for controlling the amplifier circuit of the IF signal demodulator part by its AGC voltage.

Abstract: A modulated backscatter communication system (e.g., an Electronic Shelf Label (ESL) system) includes a central node (e.g., a ceiling node) and one or more remote nodes (e.g., ESL tags). The central node transmits a downlink radio signal which is reflectively modulated at a remote node to produce a modulated reflected radio signal. At the remote node, a precise-frequency subcarrier signal is modulated with an uplink information signal to produce a modulated signal which is used to produce the modulated reflected radio signal. At the central node, the modulated reflected radio signal is received, detected and narrowband filtered to obtain the modulated subcarrier signal which is then demodulated to obtain the uplink information signal, with great immunity to close to carrier downlink radio noise and fluorescent light backscatter interference.

Abstract: A device of a vehicle for data transmission to a stationary beacon 91), which has a transceiver, comprising an on-board unit (2) with an antenna (6) for receiving a continuous signal (5), broadcast by the beacon (1), and for transmitting the received signal (5) back after modulation with a data signal (i(t)), is characterized in that the signal (7) transmitted back by the on-board unit (2) is a double-sideband signal. In that case, the on-board unit (2) can be designed as extremely simply and in the simplest case comprises a diode (9) connected to the base of the antenna (6).

Abstract: Known tags which are capable of receiving and demodulating signals by way of one and the same antenna and by way of one and the same diode, as well as being capable of modulating and transmitting signals, often have a poor efficiency, particularly if the antenna is implemented in the form of a flat plate. By coupling a high-ohm first terminal of the antenna to the diode, and coupling a low-ohm second terminal to earth by way of an inductive element, there is obtained a tag which has a good efficiency, both regarding the reception and demodulation of signals and regarding the modulation and transmission of signals.

Abstract: A modulating reflector circuit arrangement comprising a transistor configured by means of a feedback arrangement upon operation within a linear region of the transistor's current/voltage characteristic to reflect an incoming amplitude modulated signal with an increased amplitude and a modulator operable to modulate power to the transistor with a periodic waveform in which the reciprocal of the period of the periodic waveform is the required sideband frequency of the reflected signal and the waveform is selected such that the arrangement reflects a substantially single sideband signal.

Abstract: An electromagnetic interference (EMI) shield for a handheld cellular phone that is particularly useful for shielding a hearing aid against EMI from the phone's antenna. The device includes a base and a flap laminated with a metallic shielding. The base attaches to the receiver end of the cellular phone and the flap rests over the base when the phone is not in use. In operation, the flap extends away from the base forming an enclosure about the user's ear for shielding the hearing aid from EMI when the phone is in use.

Abstract: A modulated retroreflection system for secure two-way communication and identification includes a transceiver at a first location and a transponder at a second location. The transponder receiving, modulating, and reflecting the signal back to the transceiver includes a retroreflector having a at least one reflective surface coated with an electro-responsive material. The electro-responsive material modulating the reflection coefficient of the reflective surface thereby modulating signals reflected by the surface. The transponder further includes a modulator electrically connected to the electro-responsive material for applying a modulated bias voltage thereby modulating the refractive index and consequently the electrical phase, and/or amplitude of the reflected signal.

Abstract: In accordance with the present invention, an RFID system has a homodyne receiver having two outputs; the in-phase or I output and the quadrature or Q output. The modulated backscattered signal is composed of an information signal, modulated onto a single frequency subcarrier signal, generating a modulated subcarrier signal; this modulated subcarrier signal is then backscatter modulated onto the incoming RF signal. To demodulate this modulated backscattered signal, the I and Q outputs are combined using an IQ combiner. This IQ combiner introduces a 90.degree. phase shift, with respect to the frequency of the subcarrier signal, onto one of the demodulator outputs and then combines the outputs of the demodulator.

Abstract: A communication area for an antenna disposed on a toll collection gate and a communication area for a responder unit (IU) mounted on an automobile are arranged to coincide with each other. Communication failure in overlapping areas where a plurality of communication areas are formed in a toll collection area is prevented. When an IU receives a pilot signal-wave, a carrier-radio-wave-signal is subsequently transmitted thereto. The IU modulates the carrier-radio-wave-signal with a responding data-signal and transmits the modulated-carrier-radio-wave as a responding signal-wave. In this system, the output power of the responding signal-wave is attenuated during the round trip of the carrier-radio-wave. Therefore, the output power thereof is decreased from an original level when the pilot signal-wave is transmitted.

Abstract: A radio communication system includes an Interrogator for generating and transmitting a first modulated signal by modulating a first information signal onto a radio carrier signal, the first information signal indicating in which of multiple response modes a receiving Tag should respond. One or more Tags of the system receive the first modulated signal and decode it to obtain the first information signal. A Backscatter Modulator modulates the reflection of the first modulated signal using a second information signal whose content, data rate, or modulation is determined by said first information signal, thereby forming a second modulated signal. The Interrogator receives and demodulates the second modulated signal to obtain the indicated second information signal.

Abstract: A duplex radio communication system includes an Interrogator which generates a first modulated signal by modulating a first information signal onto a radio carrier signal. The Interrogator transmits the first modulated signal to at least one remote Tag of the system. The remote Tag receives and processes the first modulated signal received at its Antenna. A Backscatter Modulator uses a second information signal to modulate the reflection of the first modulated signal from the Antenna, the reflected signal being a second modulated signal. The Interrogator receives and demodulates the second modulated signal to obtain the second information signal.

Abstract: A modulated backscatter communication system (e.g., an Electronic Shelf Label (ESL) system) includes a central node (e.g., a ceiling node) and one or more remote nodes (e.g., ESL tags). The central node transmits a downlink radio signal which is reflectively modulated at a remote node to produce a modulated reflected radio signal. At the remote node, a precise-frequency subcarrier signal is modulated with an uplink information signal to produce a modulated signal which is used to produce the modulated reflected radio signal. At the central node, the modulated reflected radio signal is received, detected and narrowband filtered to obtain the modulated subcarrier signal which is then demodulated to obtain the uplink information signal, with great immunity to close to carrier downlink radio noise and fluorescent light backscatter interference.

Abstract: In a communication system for data transmission from a moving vehicle to a stationary beacon (1) which has a transceiver in which a signal is broadcast by the beacon (1) and received by an antenna (5, 5') of an on-board unit (4) of the vehicle and after a modulation with a data signal is transmitted back again to the beacon (1), where the data are extracted from the returned signal, the reliability of transmission for the data is increased by providing that the on-board unit (4) has at least two modulators (6, 6'), with which independently of one another the received signal is modulatable with the data signal and can be transmitted back in different ways. The transmission in different ways of the signals modulated independently of one another can be done by means of spatial separation of the antennas (5, 5') and/or by means of polarizing the broadcast signals differently from one another.

Abstract: An electric field absorption light modulation unit includes a light emission device for emitting light and a modulation device for varying a light transmittance thereof of light applied by the light emission device so as to provide the light as a result of modifying thereof. A driving signal generating unit coupled with the electric field absorption light modulation unit generates a driving signal to be applied to the modulation device from an input information signal by making the modulation device vary the light transmittance thereof, and the driving signal generating unit provides the driving signal so that the driving signal in a fluctuation range in which an undesirable level fluctuation may be present, corresponds to a constant working range of the modulation device, the light transmittance thereof staying at a constant value in the constant working range.