Abstract: A digital control device for tracking a sine wave according to the present invention has a compensator, a control object and a feedback gain. An input into the compensator is a signal obtained by subtracting a control quantity from a reference value. An input into the control object is a signal obtained by subtracting an output of the feedback gain from an output of the compensator. A transfer function of the compensator is (k2z+k1)/(z2?2z cos ?T+1), where ? is an angular frequency, T is a sampling period, z is a z operator, and k1 and k2 are constants. Thus, a second-order compensator can be configured, with which a sinusoidal reference waveform can be tracked simply and with high accuracy.

Abstract: The present invention provides ultra-wide band communication systems and methods, including multi-band ultra-wide band communication systems and methods. Methods and systems are provided in which frequency sub-bands of an ultra-wide band spectrum are allocated for signal transmission. An ultra-wide band transmission including the information is sent, including sending a signal over each of the plurality of sub-bands. Methods are further provided in which a first data signal containing information is converted into an encoded signal using an Inverse Fast Fourier Transform. The encoded signal is converted into an encoded ultra-wide band signal that can be pulsed or transmitted using burst symbol cycles. The encoded pulsed ultra-wide band signal is decoded using a Fast Fourier Transform to obtain the information.

Abstract: The present invention is to provide an inexpensive transmission apparatus which has the function of receiving standard television broadcasting, uses a minute-power wave, and is able to coexist with future digital television broadcasting or mobile communication equipment which will use the same frequency band as that of the transmission apparatus. By using an RF converter 102 and an RF tuner 118 which are adapted to a standard television signal, available frequencies within the reception band are detected, and the use frequency is rapidly changed to spread the spectrum, thereby performing communication by the minute-power wave.

Abstract: A vehicle mounted DSRC apparatus is capable of achieving reduction in the size and cost thereof. The vehicle mounted DSRC apparatus includes an ASK data generation part 11, an I data generation part 21, a Q data generation part 22, a first band limiting filter 23A for band limiting I data and ASK data, a second band limiting filter 24 for band limiting Q data, an ASK low pass filter 12A for removing harmonic components from the ASK data, first and second low pass filters 25, 26 for removing harmonic components from QPSK data, an ASK modulator 13 for ASK modulating the ASK data, a QPSK modulator 27 for QPSK modulating the QPSK data, and a power amplifier 30 for amplifying output data of the ASK modulator 13 or the QPSK modulator 27 to a desired level thereby to output it to an antenna as an ASK modulated signal and a QPSK modulated signal.

Abstract: A local wireless system for transmitting a modulated RF carrier audio signal from a base unit to a receiver unit is provided. The base unit has a pair of audio input connections of which are coupled to an audio source amplification device for receiving left and right audio signals. The receiver unit has a pair of electroacoustic transducers (speakers) for reproducing demodulated left and right audio signals modulated upon the RF carrier audio signal. The base unit encloses a transmitting circuit having a first antenna and first, second and third circuits which modulate the left and right audio signals onto an RF carrier signal in the 900 MHz range. A receiver unit encloses a receiver circuit and is coupled to the pair of speakers. The receiver circuit performs a single downconversion of the modulated RF carrier signal from the 900 MHz range to a useable 10.7 MHz left and right signal.

Abstract: A gain controlled mixer for an integrated CMOS transceiver. Accuracy of the controlled gain may be relatively invariant over temperature, manufacturing process, and other variations attendant to circuit realizations in a CMOS transceiver, and other realizations. A plurality of substantially matched circuit elements are instantiated and disposed similarly within the gain controlled mixer, enhancing the gain accuracy of selectable gain control states. Matching gain and other functions between circuit elements is further enhanced by appropriately controlling DC operating point conditions.

Abstract: A test signal generator at a transmitter station and a facsimile generator at a receiver station go through an acquisition and tracking process which aligns the two signals so that a logical processor can compute the frequency transfer function of the entire propagation path for use in an adaptive, concurrently sent communication signal. The frequency transfer function is conveyed back to the transmit end via a control channel permitting an adaptivity function at the transmit end to influence subsequent selection of communication parameters, among which are typically transmitted data rate, selection of modulation, selection of forward error correcting coding, and selection of frequency band for transmission. The same measurement is conveyed to an adaptivity function at the receive end for use in the communications receiver to select demodulator variables such as gain control, and equalization of amplitude and phase, versus frequency.

Abstract: In a mobile communication system, a method and system for obtaining location-dependent services information by using a mobile station. An information beacon containing services information pertaining to the location of the beacon is disposed in an environment. The beacon is capable of communicating with the mobile station when the mobile station is located within the operating range of the beacon. The mobile station includes a services access key which, when selected while the mobile station is within the operating range of the beacon, will transmit a query to the beacon requesting location-based services. In response to the query, location-based services information will be transmitted to the mobile station.

Abstract: The invention indicates a method for signal processing of an amplitude-modulated and/or phase-modulated high-frequency signal (RF signal), in which the RF signal is broken down into two signals (FM1 and FM2) by relative phase displacement by an angle +? and ?? and the signals are amplified before they are added to form a transmission signal, and to a circuit arrangement in which the pure phase-modulated RF signal is multiplied in a first branch by cos ? and in a second branch by sin ? and the two signals (FM1, FM2) are obtained by respective summation and subtraction of the multiplied signals.

Abstract: A wireless communication RF circuit includes a transmitting-and-receiving antenna, a modulator circuit, an SPST switching circuit, and a demodulator circuit, which are arranged in a sequence. Upon signal reception, the SPST switching circuit is switched ON, and the demodulator circuit extracts a signal wave from a signal received by the antenna and outputs the signal wave to a control circuit. Upon signal transmission, the SPST switching circuit is switched OFF, and the modulator circuit mixes transmission data supplied from the control circuit with a carrier and outputs the carrier to the antenna. Only a single antenna is required. Upon signal reception, the influence of the modulator circuit is negligible. Upon signal transmission, the SPST switching circuit is switched OFF, thus the effect of the demodulator circuit is negligible, which greatly reduces loss.

Abstract: The wireless data communication device (1) is mounted in a portable object, such as a wristwatch. The device includes an oscillator circuit (6), which produces high frequency signals (SH), and a signal processing unit (7), connected to the oscillator circuit. The connection structure of one part of the oscillator circuit (14, 15), which produces the high frequency signals, is arranged to act as antenna for the transmission of data by means of stray signals (SP) transmitted by the connection structure. The processing unit provides a control signal (CC) to the oscillator circuit depending upon the data to be transmitted by means of the stray signals by the connection structure. An amplitude modulation or a frequency modulation can be used for the transmission of data by means of the stray signals.

Abstract: In accordance with the invention, radio program content or other audio communications and music are transmitted as digital information through the Internet to an Internet radio receiver/transmitter device. The device converts received digital information to analog information and broadcasts the information in the radio frequency band at low power in a localized area for reception by ordinary FM or AM radios. The device is capable of receiving multiple streams of different digital information, and broadcasting each of these on separate radio frequencies, so that each person in a household may hear its own selected programming on its own preselected radio frequency. It is programmable as to at least broadcast commence time, frequency and end time, if desired. Moreover, it may store received information to play at a preprogrammed time, or on demand.

Abstract: A transmitter and a receiver share a maximum number of transmission bits per symbol as a parameter. The transmitter modulates an encoded and interleaved transmission signal in accordance with a modulation scheme which enables the transmission of one bit or more per symbol, while the receiver demodulates a received signal based on a channel quality in accordance with a modulation scheme which has a higher modulation level as the channel quality is higher. When the number of demodulated bits per symbol is smaller than the maximum number of transmission bits per symbol, the receiver deinterleaves and decodes a received signal after the demodulation on the assumption that the received signal has likelihoods of zero as much as the number of missing bits.

Abstract: A high frequency signal transmission apparatus includes a transmitter for transmitting received signals from a signal source as a modulated signal on a high frequency 900 MHz carrier to a remote receiver. The remote receiver converts the high frequency carrier in at least one conversion step to a lower frequency carrier signal. The lower frequency carrier signal carrying the modulated signal is then converted to an audio output or to another carrier signal and retransmitted as a modulated second signal to another remote receiver capable of demodulating the signal and broadcasting the audio sounds or video images. The oscillators in the transmitter and receiver are selectable to operate at discrete frequencies. Automatic fine tuning control is provided in the receiver to accommodate drift of the oscillator in the receiver.

Abstract: An improvement for a phasor fragmentation engine and method, whereby a phasor flipping algorithm is applied when determining fragment phasors for a non-constant envelope modulation signal (e.g. OFDM). The phasor flipping algorithm avoids sharp phase transitions for the fragment phasors, which cause an increase in bandwidth, by performing a comparison of the phasor angle separation between the prior and current time samples. This comparison corresponds to a determination of whether the modulation signal V has passed near or through zero.

Abstract: A wireless transmission device for communicating a plurality of audio streams to remote devices may include a plurality of inputs for receiving a plurality of digital audio streams, a combiner connected to the inputs for combining control codes and the received audio streams in a predetermined format to form a signal wherein the control codes for controlling the operation of a remote device equipped for processing the signal to extract the audio streams therefrom in accordance with the predetermined format, and a transmitter connected to the combiner to transmit the signal for reception by the remote device. The transmitter may include an infra-red light emitter for transmitting the signal as an infra-red light signal.

Abstract: Bandwidth reduction of amplitude and/or phase components of relatively wide bandwidth composite signal. In an exemplary embodiment, an EER amplifier system for CDMA signal amplification includes an amplitude bandwidth reduction module included in an amplitude signal component path and a phase bandwidth reduction module is included in a phase signal component path, for controlling an RF amplifier. The phase bandwidth reduction module may reduce the phase component bandwidth of the input signal by, for example, generating a non-linear relationship between phase signal amplitude and input signal amplitude. The amplitude bandwidth reduction module may reduce the amplitude component bandwidth of the input signal by, for example, generating a non-linear relationship between the supply voltage to the RF amplifier and an input signal amplitude.

Abstract: In an on-vehicle equipment for Dedicated Short-Range Communication (DSRC) in Intelligent Transport System (ITS), a priority sequence for switching local frequencies of f1 to f7 in correspondence with types of on-road equipment is previously set, the local frequencies are sequentially outputted at a predetermined cycle in accordance with the priority sequence, a received frequency signal is compared with a selected frequency signal, and when the received frequency signal is the same as the selection frequency signal, the local frequency corresponding to these is determined as a desirable communication frequency, and the communication frequency is fixed as being this local frequency with high efficiency.

Abstract: The invention discloses a process for re-transmitting single frequency signals and a single frequency signal repeater, where coupling occurs between the transmitting antenna and the receiving antenna, and where the process is of the type used in a single frequency signal repeater and comprises the steps of: [a] receiving a first radio frequency signal having a particular receiving power, [b] optionally converting said first radio frequency signal into a process signal, [c] filtering, amplification and automatically controlling the gain of said signal, [d] canceling said coupling between said transmitting antenna and said receiving antenna, [e] reconverting, as the case may be, said process signal into a second radio frequency signal, [f] amplifying the power of said second radio frequency signal, [g] output filtering, and [g] transmission.

Abstract: A phase-selective type frequency modulator capable of easing the restriction on a phase range of a modulated clock signal. The phase-selective type frequency modulator includes a multiphase clock signal generating circuit 101 for generating N-phase clock signals; a control circuit 104 for sequentially activating one of first group of clock selection signals indicating a clock signal to be selected from the N-phase clock signals; an edge appearance time adjustment circuit 103 for adjusting a rising edge appearance time and/or a trailing edge appearance time of the first group of clock selection signals outputted from the control circuit 104 to output second group of clock selection signals; and a modulated clock signal generating circuit 102 for selecting one clock signal from the N-phase clock signals in accordance with an activated state of the second group of clock selection signals outputted from the edge appearance time adjustment circuit 103 to output a modulated clock signal MCK.

Abstract: A transmission circuit includes a baseband circuit, spreading section, multiplier, digital modulator, quadrature modulator, and antenna. The baseband circuit generates and outputs at least one transmission data constituted by first and second channel data. The spreading section spreads the transmission data with a spreading code that differs for each transmission channel. The multiplier respectively weights the amplitudes of the first and second channel data by using a combination of two gain factors determined by a transmission data rate. The digital modulator digitally modulates the first and second channel data whose amplitudes are weighted by the multiplier. The quadrature modulator quadrature-modulates the digitally modulated first and second channel data and outputs the data as a transmission signal. The antenna emits the transmission signal output from the quadrature modulator as a radio wave.

Abstract: A location update system for updating a location of a mobile terminal. The system includes a paging area with a mobile terminal present within the paging area, a domain area with the mobile terminal present within the domain area and a paging location update server that is communication with the mobile terminal and updates a location of the mobile terminal and updates the domain area.

Abstract: Briefly, in accordance with an embodiment of the invention, a method and apparatus to transfer information is provided, wherein the method includes transferring information between at least two wireless devices using a waveform that includes a first sinusoidal signal and a second sinusoidal signal, wherein the second sinusoidal signal has more zero-crossings than the first signal and wherein a duration of the first sinusoidal signal is less than a duration of the second sinusoidal signal.

Abstract: A method for WLAN signal strength determination comprises receiving a WLAN RF signal; converting the WLAN RF signal to a voltage proportional to the signal; comparing the voltage to a first reference voltage; and outputting data corresponding to WLAN RF signal strength if the voltage is greater than the first reference voltage.

Abstract: A FM transmitter and charger assembly includes a primary member, a FM transmitting device, and a securing member; audio signals in a MP3 player can be transferred to, and transmitted by the transmitting device when both the MP3 player and the FM transmitting device are connected to the primary member while a radio can receive the signals, and play music accordingly when it is tuned to the same channel as the transmitting device; the securing member includes a hollow part for the MP3 player to be closely inserted therein, and an engaging plate connected to a back of the hollow part and capable of being detachably fitted onto the primary member; thus, a certain primary member allows different MP3 players to be securely connected thereto with the help of various securing members, which have different sizes for suiting MP3 players with different sizes.

Abstract: The invention relates to a device for aiding the analysis of signals by using symbols-based digital modulation. The device includes a signal memory for storing a complex digital signal, representative in amplitude and phase of a captured signal, over a chosen duration, as well as a processor for searching for the properties relating to the carrier frequency of the complex signal and to its modulation. According to the invention, the processor includes a projector for calculating the components of the complex signal in a function basis, the function basis being parameterized according to an estimated tempo of the modulation, as well as a calculator, operating on these components so as to determine an estimate relating to a property of the complex signal, from among its elementary pulse shape, the string of symbols of the complex signal and its carrier.

Abstract: A method for sending data from a transmit site to a receive site which includes dividing a transmit data stream having a first bit rate into multiple data streams with each of the multiple data streams having a bit rate which is lower than the first bit rate, transmitting each of the multiple data streams over a plurality of RF channels and recombining the multiple data streams at the receive site to provide a receive data stream having a bit rate equal to the first bit rate.

Abstract: A wireless audio distribution system having a wireless transmitter, responsive to a plurality of audio input channels, for transmitting a encoded digital bitstream serially combining each of the audio input channel, the encoded digital bitstream further including control data disbursed therein, a receiver, responsive to the transmitted encoded digital bitstream, for decoding and demultiplexing the digital bitstream, a manual selector switch, connected to the receiver device for selecting one or more of the audio input channels to be reproduced, and a sound producing device for selectively reproducing the one or more selected audio channels in accordance with the control data.

Abstract: Herein disclosed is a wireless microphone system comprising a plurality of wireless microphones each having a microphone storage area having a unique global identification element stored therein, each of the wireless microphones operative to collect a voice, convert the voice thus collected into an audio signal, and transmit the audio signal and the global identification element; and a voice receiving apparatus for receiving the audio signal and the global identification element from a wireless microphone. The voice receiving apparatus includes a storage section for storing an identification table including a plurality of local identification elements in association with a plurality of global identification elements.

Abstract: An antenna device of an interrogator which constitutes an automatic identification system by exchanging information with an IC tag attached to an object to be identified by electromagnetic coupling is disclosed. The antenna device comprises an antenna element, and a capacitor connected in series to the antenna element and having a variable capacitance to maintain a predetermined resonance frequency. The predetermined resonance frequency is maintained by switching taps on an antenna coil. Alternatively, the predetermined resonance frequency is maintained by switching taps on a tapped inductor or by a variable inductor.

Abstract: Apparatuses, systems and methods for transmitting and receiving modulated impulse radio signals. An impulse radio receiver includes a time base, a precision timing generator, a template generator, a delay, first and second correlators, a data detector and a time base adjustor. The time base produces a periodic timing signal that is used by the precision timing generator to produce a timing trigger signal. The template generator uses the timing trigger signal to produce a template signal. A delay receives the template signal and outputs a delayed template signal. When an impulse radio signal is received, the first correlator correlates the received impulse radio signal with the template signal to produce a first correlator output signal, and the second correlator correlates the received impulse radio signal with the delayed template signal to produce a second correlator output signal. The data detector produces a data signal based on at least the first correlator output signal.

Abstract: A frequency-hopping intrapulse frequency modulation Loran-C navigation pulse technique, preferably using a flat-topped pulse shape and a novel 16-ary phase hopping scheme, and a novel improved high-power solid-state switch for dynamic antenna modulation tuning.

Abstract: A transfer connection device for wirelessly connecting mobile phone and hand-free handset has a first connector and a second connector to respectively couple with a hand-free handset and a mobile phone to allow signal transmission between the hand-free handset and mobile phone accomplished in a wireless fashion without the tangle and inconvenience of physical linking line between the mobile phone and the hand-free handset.

Abstract: A method and apparatus for notifying a user of an incoming cellular telephone call are provided. The apparatus includes a cellular telephone body having at least a back surface, a first transducer positioned within said cellular telephone body perpendicular to the back surface and adapted to generate a first acoustic field, and a second transducer positioned coaxially to the first transducer and adapted to generate a second acoustic field. A first frequency generator is coupled with the first transducer to drive the first transducer to generate the first acoustic field and a second frequency generator is coupled with the second transducer to drive the second transducer to generate the second acoustic field in response to an indication that an incoming cellular telephone call has been received. The first and second acoustic fields overlap. The overlapping fields generate a vibrational sensation from a difference of frequency from unequal frequencies generated by the first and second transducers.

Abstract: An Automatic Frequency Control (AFC) circuit for a mobile terminal employs a fractional-N Phase Locked Loop (PLL) to directly reduce errors in the synthesized frequency, such as due to component tolerances, temperature drift, and the like. The frequency error is detected by the average speed of rotation of the I,Q constellation. A corresponding offset is added to the tuning frequency selection word prior to encoding, such as in a ?? modulator, to generate an effective non-integer PLL frequency division factor over a specified duration. The ?? modulator may include dithering the different integer values by a pseudo-random number to minimize noise in the output frequency spectrum introduced by the fractional-N division. Component and parameter selection allow a high degree of resolution in frequency control of the fractional-N PLL. By directly controlling for the frequency error, a DAC and XTAL oscillator tuning circuit may be eliminated from the AFC circuit.

Abstract: The present invention provides for a first modulation at an arbitrary frequency and a second modulation at another arbitrary frequency. To achieve this, the present invention demodulates the first modulation using the same reference oscillator signal that was used in the first modulation. Because modulation and demodulation are achieved using the same reference oscillator signal, a close approximation of the original signals is achieved. With this close approximation, a subsequent re-modulation can be readily achieved at a second arbitrary frequency and can further be achieved using low-cost synthesizer and modulation components. In effect, a first modulation is achieved at a first frequency; the first modulation is then demodulation to zero frequency; and, in turn, a second modulation (i.e., re-modulation) is achieved at a second frequency.

Abstract: A method of communicating of the present invention includes broadcasting a signal from a transmission point. The power of the signal is limited such that the signal will attenuate within a predetermined distance from the transmission point. The signal is received by a receiver. A communication system includes a transmitter and a receiver. The transmitter is adapted to broadcast a first signal which attenuates within a predetermined distance from the transmitter. The receiver is adapted to receive the first signal. The method and system can be used to imperceptibly transmit voice data.

Abstract: Methods and apparatus for creating, transmitting and receiving ultra-wideband pulses through wire media are presented. One embodiment of the present invention transmits ultra-wideband pulses that occupy radio frequencies that are not used by other electromagnetic signals present in a wire medium of interest. Other embodiments of the invention may create, transmit, and receive ultra-wideband pulses that use radio frequency(s) that are not used by other signals present on wire media within a wire network of interest. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Abstract: A pulse data coding method for wireless signal transmitting and receiving devices includes the steps of using a transmitter to transmit a signal of pulse data to be transmitted, transmitting at least one identification code pulse signal after a predetermined time interval from the transmission of the pulse data signal, and transmitting a check code pulse signal after another predetermined time interval from the transmission of the identification code pulse signal. The check code pulse signal is obtained by coding the pulse data signal and the identification code pulse signal according to a predetermined coding process. When a corresponding receiver receives the signal from the transmitter, it determines a correctness of the received signal according to the predetermined coding process, which may be an algorithm of addition, subtraction, multiplication, division, and/or a ratio operation.

Abstract: A wireless output input device (WOID) digital audio player for storing and/or receiving digital audio and preserving the digital stream without the inherent distortion of translating the stream to analog prior to modulation and transmission, which includes an FM receiver, and an FM transmitter for transmitting the audio to an external FM radio or receiver. The device automatically and periodically scans a plurality of channels on the FM band to determine the channel having the least amount of interference and then tunes the FM transmitter to the frequency of that channel and displays the channel to which the external receiver should be tuned. A remote control may be provided to selectively transmit signals to the player's FM receiver for controlling operation of the player.

Abstract: An audio player assembly comprises an MP3 player and an audio player unit operatively coupled with such MP3 player for receiving audio signals from the MP3 player. Specifically, the audio player unit comprises at least one speaker for outputting audio signals generated by the MP3 player and an FM received operatively coupled with the speaker.

Abstract: A unified digital front end filtering circuit is described for IEEE 802.11g protocol compliant systems. The front end uses polyphase rate conversion filters cascaded with channel extraction and pulse shaping filters to accommodate the different sampling rate requirements for orthogonal frequency division multiplexing (OFDM) and direct sequence spread spectrum (DSSS) modulation, which have to be supported simultaneously, without using separate analog front ends.

Abstract: The invention relates to a method for use in wireless data communications for facilitating two way data transfer between devices employing frequency diversity. It is generally suited toward units accomplishing frequency diversity by way of frequency hopped spread spectrum operation. The basic unit of the invention is an individual data frame whose reliability is enhanced by a unique combination of redundant error correction coding, time-, and frequency-diversity. The invention further extends the individual data frame concept to a complete asynchronous data message which comprises both a call establishment phase and a traffic phase. The traffic phase extends the basic data frame to encompass a complete data message. That message, which already contains the enhancements of the basic data frame, is further enhanced by repeating itself as many times as can fit in the transmission.

Abstract: A transmitter for transmitting a high frequency transmit signal generates a low intermediate frequency quadrature signal, and up-converts the low intermediate frequency quadrature signal to the high frequency transmit signal. The frequency spectrum of the high frequency transmit signal has a transmit band and a sideband corresponding to the transmit band. The transmit band is confined to a total transmit band outside of which severe sideband filtering requirements.apply. Before up-converting, the transmitter provides that the sideband falls at a side of the transmit band such that the sideband falls within the total transmit band.

Abstract: An RF carrier signal is frequency modulated by a modulating signal, as a function of the amplitude of the modulating signal. The number of cycles in the frequency modulated carrier is counted in a first counter during the positive half cycle of the modulating signal and in a second counter during the negative half cycle of the modulating signal. A microprocessor obtains the difference of the counts in the counters, and from the difference computes the deviation of the modulated carrier from the center frequency of the carrier. This is compared with a desired deviation and the microprocessor calculates and generates a correction signal to vary the amplitude of the modulating signal when the difference between the computed and desired deviation exceeds a predetermined value. An arrangement is also provided whereby, after a calibration procedure, an external source may provide the modulation signal.

Abstract: A communications interface device (4) has circuitry for receiving digital signals in the form of characters according to a protocol defining that a communications link is initialized by a series of start characters, each having a specified duration. The receiving circuitry can assume a first state in which characters can be detected, and a second state in which detection of characters is not possible. Power consumption is higher in the first state than in the second state. The device can alternate the receiving circuitry periodically between the first state and the second state with a period shorter than the duration of the series of start characters. In each period the receiving circuitry assumes the first state for a time longer than the duration of a start character. A communications link is established if a character is detected. The power consumption can be reduced considerably without causing unnecessary inconvenience and time consumption for the user.

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: A method of synchronizing wireless communication between computer (16) having a transmitter (24) and a peripheral device (50) having an amplitude modulated (AM) receiver (54) and at least one frequency modulated (FM) receiver (56) which communicates via radio frequency signals. The computer (16) partitions the data (28) into a plurality of data blocks (30), spreads the data blocks (30) over a plurality of frequency channels (38) within a predetermined range (70), and selects one of the channels (32) for transmitting the signal (40). The resulting signal (40) has increased and decreased frequency corresponding to the data block (30). The peripheral device (50) detects the signal (40) as being present and begins measuring a time period (64) with the AM receiver (54). The method is characterized by scanning the plurality of frequency channels (38) with the FM receiver (56) during the measured time period (64).

Abstract: A communications device such as a personal identity card is in the form of a badge or label worn on the outside of the wearer's clothing. The badge includes a first layer of a transparent material having an inner surface that is contoured with a retroreflecting repeating pattern. A second layer also of a transparent material has an inner surface with a reciprocating retroreflecting pattern. Sandwiched between the two layers is a layer of liquid crystal material the refractive index of which can be varied through the application of an electric field. When the refractive index of the layer is close to that of the first and second layers, incident radiation passes through the device with little scattering. However, as the refractive index of the layer is varied by application of an electric field, incident radiation is retroreflected from the contoured interface of the first layer with the layer.

Abstract: An FM transmitter and power supply/charging assembly electrically coupleable with an MP3 player. The assembly includes a modular docking unit having a main body portion with a docking cavity therein, wherein the main body portion contains the FM transmitter and power/charging circuitry, with coupling means in the docking cavity for connecting the MP3 player with the FM transmitter and power/charging circuitry, to accommodate FM transmission by the FM transmitter of audio content when played by the MP3 player in the docking cavity of the modular docking unit, and adapted for transmitting electrical power through the modular docking unit and the power/charging circuitry therein, for charging of a battery of the MP3 player and/or powering of the MP3 player.