Abstract: A first antenna (16) at a user location (14) receives signals at a first frequency where the signals are travelling only within a first directional reception range as measured from a centerline (28) of the first antenna (16). The first antenna (16) has its centerline (28) aligned to receive direct broadcast satellite signals transmitted from a satellite in geosynchronous orbit about the earth. A second antenna (18) at the user location (14) receives signals at the first frequency where the signals are travelling only within a second directional reception range as measured from a centerline (30) of the second antenna (18). The second antenna (18) is aligned to receive signals transmitted at the first frequency from a terrestrial transmitting location remote from the user location. A terrestrial transmitter transmits signals at the first frequency and directionally within a terrestrial azimuth range from the terrestrial transmitting location.

Abstract: An antenna alarm detection system includes first and second antennas, a transmission section, an antenna switch section, a reflected power detection section, and a comparing section. The transmission section transmits a control signal and speech communication information. The antenna switch section alternately switches and outputs the control signal transmitted from the transmission section to the first and second antennas in a predetermined cycle in a non-speech communication state in which only the control signal is transmitted. The reflected power detection section detects the reflected power of each of transmission signals from the first and second antennas. The comparing section compares the detected reflected power with a predetermined reference value, and outputs an alarm signal on the basis of the comparison result.

Abstract: A design of equally loaded, under varying traffic load conditions, power amplifiers for a multibeam satellite is presented. Each output beam contains signals of only one beam corresponding to its input beam. The output beams are shaped to produce a small reduction of power at the crossover point of adjacent beams. MMIC and high Tc superconducting designs, including the design of high Tc superconducting reflector antenna, are presented.

Abstract: An apparatus for eliminating interference caused by spurious signals includes a reference oscillator (127) and a controller (114). Circuitry (500) in a communication device (104) incorporating the apparatus operates at a rate set by a system clock signal (CLOCK). The communication device (104) communicates on any one of a plurality of different channels. The reference oscillator (127) outputs the system clock signal (CLOCK) at a first frequency which generates spurious signals on at least one of the plurality of different channels. The controller (114) shifts the system clock signal (CLOCK) by a first predetermined amount to a second frequency when the communication device (104) is to be tuned to the at least one of the plurality of different channels so as to remove the spurious signals from the at least one of the plurality of different channels.

Abstract: Diversity reception apparatus includes a number of receivers each having a distortion detector. There is a common output channel. A comparator compares the signals detected by detectors and provides a control signal to a selector or switching circuit that couples that receiver having the preferred received signal to the common output channel.

Abstract: Earth-fixed cell beam management methods which may be employed to allocate beams generated by a constellation of low Earth orbit satellites (12) flying in orbits below geosynchronous altitudes are disclosed. These beams (19) are electronically steered so that they illuminate "Earth-fixed cells" (26) as opposed to "satellite-fixed cells." Beam steering apparatus using a spherical dielectric lens (106) is disclosed. In a system that employs satellite-fixed cells, the "footprint" of the beams propagated by a spacecraft defines the zone on the ground called a "cell" which is illuminated by the spacecraft. This satellite-fixed cell moves constantly as the spacecraft moves around the globe. In sharp contrast, an "Earth-fixed cell" (26) is a stationary region mapped onto the surface of the Earth (E) that has permanent fixed boundaries, just like a city or a state.

Abstract: An amplifying apparatus for linearly amplifying a desired signal using a pair of coupled non-linear amplifiers is disclosed. The amplifying apparatus comprises a limiter for separating amplitude variations from the desired signal and producing a constant amplitude signal bearing the phase of the desired signal and an amplitude related signal. In addition, a drive signal generator produces two drive signals each dependent on the constant amplitude signal and the amplitude related signal such that each drive signal depends on the phase of the desired signal and such that the sum of the squares of the amplitudes of the drive signals is constant.

Abstract: A satellite-based, world-wide cellular messaging system (5) transmits paging messages to pagers (2) via multiple beams. A pager (2) monitors multiple beams, recording the schedules for each beam, and by combining the schedules for multiple beams, ultimately determines which frames in the message groups to monitor for messages. As propagation characteristics degrade, an adaptive method refines the criteria for including frames into a monitoring schedule.

Abstract: Band-pass filters BPF1, BPF2, and BPF3 correspond to the reception frequency band for FDD, the transmission band for FDD, and the band for TDD, respectively. An antenna A1 is used in common for transmission and reception in the FDD and TDD systems. Another antenna A2 is used for diversity reception in the FDD system. A controller 20 controls switches SW1 through SW4. When the FDD system is selected, the reception signal is sent from the antenna A1 or A2 through the filter BPF1 to a reception amplifier RA, and the transmission signal is sent from the transmission amplifier TA through the filter BPF2 to the antenna A1. When the TDD system is selected, the reception signal is sent from the antenna A1 through the filter BPF3 to the reception amplifier RA, and the transmission signal is sent from the transmission amplifier TA through the filter BPF3 to the antenna A1.

Abstract: A diversity apparatus for a global positioning system antenna capable of selectively using a better receiving sensitivity antenna among antennas is disclosed. The invention includes at least two antennas; first and second amplification comparing means for amplifying signals received from the antenna through a low noise amplifier and a coupling line and for comparing a direct current with a base voltage; selection means for selecting one antenna among the antennas by activating an impedance line; and first and second connection means for determining from the amplified signals, which of the antenna signals to output, and outputting the alternating current signal from that antenna.

Abstract: An interference canceler comprises a first complex multiplier for multiplying a signal recovered from a quadrature modulated carrier by a first correlation value, and a second complex multiplier for multiplying a delayed version of the recovered signal by a second correlation value. The outputs of the multipliers are additively combined in an adder and subtractively combined in a subtractor. The output of the adder is amplified by an AGC amplifier to produce a reference signal representative of the envelope of the adder output. First correlation between the recovered signal and the reference signal is detected and the first correlation value is derived therefrom and second correlation is detected between the delayed version of the recovered signal and the reference signal and the second correlation value is derived therefrom. One of the outputs of the amplifier and the subtractor is selected by a selector.

Abstract: Dual program audio apparatus is provided having two or more sources of input audio program signals, switching circuitry for selecting two of the input audio signals for amplification, one or more amplifiers for amplifying the selected input audio program signals, and one or more audio speakers for enabling a listener to hear both audio programs simultaneously. Volume control circuitry is provided for selecting a higher volume level for a foreground program and a relatively lower volume for a background program and circuitry is provided for selectively interchanging the foreground and background programs either instantaneously or gradually and continuously.

Abstract: A data receiver (110) for processing multiple signals includes a receiving circuit (120) for demodulating at least first and second signals and a selector (125) coupled to the receiving circuit (120) for comparing the at least first and second signals to estimated peak and valley values. The selector (125) generates error values associated with the at least first and second signals and selects a data symbol associated with one of the estimated peak and valley values based on the error values. A timing circuit (140, 150) activates the selector (125) at predetermined times, and a controller (140) coupled to the selector (125) and the timing circuit (140, 150) recovers information in accordance with the data symbol and other data symbols.

Abstract: The present invention relates to a communications system between low-orbit satellites and terminals, in which the beams (12) of each service area (14) are illuminated according to a beam-hopping spatial scanning. For each satellite and for each terminal transmission and reception are separated in time and synchronized. Time-division duplex is used. Applicable especially to the field of space telecommunications.

Abstract: In a remote-control communication system, a signal generating unit includes a first signal transmitter for transmitting a first signal at a first frequency, such as UHF, a second signal transmitter for transmitting a second signal at a second frequency, such as an infrared frequency, that is diverse from the first frequency; a keyboard for generating an information signal containing a given message, which is modulated onto both the first signal and the second signal; wherein both the first and second modulated signals are transmitted in response to a key of the keyboard being pressed to generate the information signal. A receiver for the system includes a microcontroller for processing the given message to control a given operation of an electronic communication apparatus; a UHF detector and demodulator unit and an infrared detector and demodulator unit, which respectively detect and demodulate the first and second modulated signals to provide the information signal containing the given message.

Abstract: A radio communication device (50) has a housing having a first housing element (51) and a second housing element (53). The first housing element (51) is movable between an extended and a closed position. The radio communication device has at least two antennas (112, 113). A switch (121) is provided that is operable to switch between a first antenna (112) and a second antenna (113) responsive to position of the first housing element (51). Preferably the first antenna (112) is disposed in the first housing element (51) and the second antenna (113) is disposed in the second housing element (53) or a battery housing (57).

Abstract: A system for wireless communication between at least one first station and a plurality of second stations using a relay station is disclosed. The relay station contains, among other features, an antenna array and a multi-channel transponder. The antenna array has a plurality of antenna elements which are divided into two sets. The first set is used to provide transmission or reception using beams having a first beamwidth and the second set is used to provide transmission or reception using beams having a second beamwidth. The multi-channel transponder, which is connected to the antenna array and a feeder link antenna, receives feeder link signals from at least one of the first stations and converts the signals into drive signals for the antenna array elements. The multi-channel transponder has a first channel bandwidth for channels transponding signals for transmissions having the first beamwidth and a second channel bandwidth for channels transponding signals for transmissions having said second beamwidth.

Abstract: An electronic paging system and method for transmitting paging signals over a broadcast network, such as a standard pre-existing commercial radio broadcast system, adds paging signals to a normal radio baseband signal for non-interferential co-transmission therewith over the existing standard radio broadcast transmission system. A telephone interface receives paging information via normal telephone lines. The paging information is used to pseudo-randomly frequency-hop a frequency-synthesized signal which is added to the baseband audio of a standard commercial radio signal. This composite signal is then used to modulate the standard commercial radio broadcast carrier in the normal manner. Mobile pagers, or "beepers," receive and selectively decode (i.e. pseudo-randomly frequency-dehop) the standard commercial broadcast signal to determine whether and which pager is being summoned, i.e. addressed.

Abstract: An integrated RF avionics system having a common IF interface for diverse functions, such as radar, electronic waveform(EW) and communications/navigation/identification(CNI). The interface uses a segmented band of IF frequencies which are subdivided into two or more individual band segments separated by a guard band segment. The lower frequency band segment comprises a narrow band segment which is assigned to radar functions while the other or upper band segment comprises a wideband segment assigned to other functions such as EW and CNI functions. The guard band is not used for signal transmission, but is left unused to permit bandpass filters to reject signals in the adjacent unwanted segment, thus achieving frequency separation across the IF band while allowing the use of common hardware. The total IF range is sufficiently wide that radar, EW and CNI signals can be separated from each other with practical filters while being routed through a common IF switch network.

Abstract: The present invention discloses an apparatus for minimizing the effects of destructive interference caused by multipath fading. An amplitude sensing module receives IF signals from a plurality of receivers and generates high speed voltage signals proportional to the logarithm of the amplitude of each of the IF signals. An analog logic module compares the high speed signals to each other to determine the high speed voltage signal having the greater level and actuates a switch to select the audio output from the receiver having the high speed signal with the higher voltage level. The switched audio output of the analog logic module is filtered by an output filter module to remove switching transients generated within the analog logic module. The filter module is programmable to accommodate various IF bandwidths and response characteristics.

Abstract: A bus type clock supplying system in a communication system with master-slave synchronization includes communication cards connected with transmission lines within a communication system and a clock bus. Each communication card includes a clock supplying section including a frequency divider for extracting a clock from the transmission lines and a tri-state device outputting the clock to the clock bus; a clock receiving section including a clock selector for selecting one clock from a plurality of the bus-type clock lines, and a frequency multiplier for multiplying the frequency of the selected clock; and a monitoring and controlling section having a function of monitoring interruption of clock input, abnormalities in the frequency multiplier, etc., and a function of controlling the tri-state device and the clock selector.

Abstract: A radio frequency (RF) antenna switch (136) and associated method of operating the same is provided for switching between a first antenna (109) and a second antenna (111). A first mixer (125) has an input terminal 124 coupled to the first antenna (109) and has an output terminal 126. A second mixer (129) has an input terminal 128 coupled to the second antenna (111) and has an output terminal 130 coupled to the output terminal of the first mixer (125). The first mixer (125) and the second mixer (129) are alternatively enabled responsive to the state of an antenna select signal (141). Additionally, the common output terminals 126 and 130 of both the first mixer (125) and the second mixer (129) are matched to a first intermediate frequency stage (131). The RF antenna switch (136) advantageously provides low loss and low current drain.

Abstract: A satellite-based communication system providing high rate transfer of data between linked terminals. The system comprises a plurality of user terminals (VSAT's) that are linked by and that communicate with each other by way of a satellite-based relay system. A network control center provides configuration signals that control the satellite relay system and coordinate linking of terminals to each other. Frequency division multiplexing uplinks are used from the terminals and the network control center to the satellite relay system. Time division multiplexing are used on downlinks from the satellite relay system to the terminals and the network control center. Each user terminal comprises a data compression and decompression circuit, a transceiver, and an antenna for transmitting and receiving data to and from the satellite relay system. The satellite relay system comprises a satellite, a wide area antenna, a plurality of receive antennas, a plurality of transmit antennas, and a signal processor.

Abstract: For preventing a mobile radio terminal station from causing an interruption of communication on changing of a communication system, a receiving apparatus receives a main and a supplementary modulated signal at a boundary area which is between a main and a supplementary service area. The main and the supplementary modulated signals are modulated in a main and a supplementary modulation system, respectively. A first processing circuit (23) processes the main and the supplementary modulated signals into a first processed signal under control by a control circuit (28). A second processing circuit. (24) processes the main and the supplementary modulated signals into a second processed signal under control by the control circuit. In accordance with the first and the second processed signals, a signal producing circuit (25) produces a local signal. A switch circuit (26) selects one of the first processed, the second processed, and the local signals under control by the control circuit.

Abstract: A diversity receiver employing maximum-likelihood-sequence estimation employs a separate channel estimator (44-1, . . . , 44-L) for each of a plurality of diversity channels. Each channel estimator (44-1, . . . , 44-L) produces channel-model parameters ([f.sub.1 ], . . . , [f.sub.L ]) that characterize their respective channels. A weighting-and-accumulation circuit (56) computes the responses of the thus-represented models to candidate symbol sequences, and metrics indicating the likelihoods that respective candidate sequences were the sequences actually sent are determined by comparing the model output with the received signal in a comparison circuit (58) and squaring the magnitudes of the results in a squaring circuit (60). The receiver then employs a Viterbi algorithm (62) to determine which sequence is the one most likely to have been sent.

Abstract: Methods for transmitting and receiving radiated energy (15a, 15b, 15c) from and to a satellite (12) which moves with respect to the Earth's surface are disclosed. The invention pertains to any satellite (12) which is not in an equatorial orbit at geosynchronous altitude. The present invention reduces hand-off overhead in systems that utilize satellite-fixed cells, augments frequency re-use, and enhances the communications and sensing capacity of the satellite. In accordance with the methods of the invention, satellite footprints (16a, 16b, 16c) are partitioned into linear spanning cells (18) and multiple linear segments (22). The linear spanning cells (18) resemble long strips that extend across an entire footprint (16a, 16b, 16c). Multiple linear segments (22) are smaller contiguous areas that lie within the linear spanning cells (18). The alignment of the linear spanning cells (18) across a footprint (16a, 16b, 16c) is determined by a correction angle .phi.

Abstract: A communications satellite is disclosed which uses distributed multiplexing and demultiplexing so as to minimize the amount of cabling needed between deployable phased array panels and a central processor. Signals are distributed from the active array panels to a number of active antenna elements. Each active antenna element has at least a radiating element, a modulator and a sample and hold circuit for forming modulation waveforms.

Abstract: An FM radiowave receiver includes a diversity antenna system responsive to signal strength and noise levels. The signal strength and noise detectors generate representative signals that are compared with a threshold value for determining the input to a control for the antenna switch alternately connecting two or more antennas to the front end of the FM receiver. The present invention provides an adaptive threshold for each of the signal strength and noise signals so that the switching is limited to significant changes in signal strength and noise levels. In the preferred embodiment, the noise level threshold is adapted as a function of the modulation level of the audio composite signal delivered from the FM detector to the FM stereo decoder of the receiver.

Abstract: A satellite system includes circuitry for forming at least a first and second set of antenna beams for communication with a respective first and second set of mobile stations. Neighboring beams in the first set intersect at an approximately -4 dB down point relative to the central beam peak, thereby defining for each beam an approximately -4 dB beam circumference having an approximately -4 dB beam diameter. The second set of antenna beams are displaced from the first set of antenna beams by less than the approximately -4 dB beam diameter.

Abstract: Disclosed herein are methods and apparatus for detecting the presence of a CDPD carrier in a channel of a cellular system (although the invention is broadly applicable to detecting a specific kind of carrier associated with an "overlay" system, wherein an "overlay" system is one that shares the frequency allocation of another system on a non-cooperating basis). This specification describes a spectral estimation technique for detection of a CDPD carrier. In addition, this specification describes an MMSE (minimum mean-squared error) method that improves on the spectral estimation method.

Abstract: A radio access method for facilitating communication between at least one first station and a plurality of second stations is disclosed. First, each signal intended for transmission is buffered at a first station. The signals are then divided into equal length segments. The signal segments intended for a particular one of the second stations is transmitted using a corresponding time slot in a regularly repeating time multiplex frame. The signal segments transmitted by the first station are received at at least one of the second stations and the signal segments are assembled from successive corresponding time slots to reconstruct said intended signal. A transmit frequency channel uniquely associated with the corresponding receive time slot is determined at the second station.

Abstract: A called subscriber unit's geographic location is provided by a gateway and translated to location coordinates of a global coordinate system. The gateway identifies an orbiting satellite communication station servicing the subscriber unit's location, and sends the subscriber unit's ID and location data to the satellite. The subscriber unit's location data is translated to an angle and range relative to the satellite's nadir using the satellite's ground track data. The angle and range are mapped to an antenna beam where the subscriber unit is located using a look-up table onboard the satellite. An acquisition or ring-alert signal is transmitted within the antenna beam where the subscriber unit is located. When the range is outside the satellite's footprint, the subscriber unit's ID and location data are routed directly to another satellite currently servicing that location.

Abstract: An earth station transceiver (210) is provided for communicating with at least one satellite (110, 120) in orbit. The earth station transceiver (210) has an antenna with an array of antenna elements (220, 230) and steering circuitry (240) for steering an antenna pattern created by the array of antenna elements. A position of a beam (310-330) from a satellite can be represented by a beam number. The antenna pattern can be determined without taking signal quality measurements when the beam is at an extreme elevation angle as represented by the beam number. Signal quality measurements can alternatively be made during a time slot or frame to choose an antenna pattern instead of choosing an antenna pattern based on satellite beam number when the beam is not at an extreme elevation angle. Signal quality measurements using the same antenna pattern are made to perform an intra-site handoff. Signal quality measurements using all antenna patterns are made to perform an intersite handoff.

Abstract: A diversity receiving apparatus includes a plurality of receivers, each of which receives a plurality of signals and includes a detector which selects and outputs a desired signal from the received signals, and a delay circuit which delays the desired signal to produce a delayed signal. A level comparator compares signal levels of the desired signals outputted from the detectors with one another, and produces an output indicating which one of the desired signals has a highest signal level. A selector responsive to the output of the level comparator selects and outputs the delayed signal produced by the delay circuit delaying the desired signal having the highest signal level. A demodulator demodulates the selected delayed signal.

Abstract: The invention relates to a radio communication system and method for minimizing co-channel interference. The system comprises a plurality of mobile stations in communication with a ground based station via an orbiting satellite. The orbiting satellite transponds a combination of signals received from the mobile stations to the ground station in coherent fashion. At the ground station, the combined signals are processing using matrix models to separate the plurality of mobile station signals. The coefficients of the matrix are chosen to minimize interference between channels. Communication in the reciprocal direction proceeds in like manner. The system and methods are applicable to, for example, landmobile communication, satellite communications system and hybrids thereof. In the landmobile or satellite communication environment, the system may include directional antennas.

Abstract: An optically-based communication system hosted on an elevated platform (e.g., a satellite a tower, or other platform having a substantial vantage point) that uses multiple spatially diverse transmit and receive beams that are optically cross coupled to fully reuse the spectrum and which will create a fully interactive, high bandwidth, high capacity, fully switched communication system. The elevated platform (i.e., satellite, orbiting or tethered vehicles, airborne platforms, towers, etc.) reuses its assigned bandwidth in each of (N) multiple beams (or sectors). The beams are formed by either RF or optical means. The specific users in each beam are then spatially separated in frequency by use of an optical "Bragg Cell." The separated signals are then duplicated through a half mirror and a full mirror and recombined optically to create outputs that are unique combinations of frequencies from each full set of input beams.

Abstract: A method and apparatus for receiving square root cosine pulse uplink transmissions from a transmitting Time Division Multiple Access radiotelephone to activate a switch. Upon initial activation of the switch the apparatus will operate in a dual mode method, that method being from either a TDMA or Analog transmission signal. The apparatus utilizes receivers tuned to decode transmitted time slot frequencies of a TDMA radiotelephone and an analog signal rectifier receiver for analog radiotelephone transmissions to activate a means of audible, visual, mechanical and other notification methods.

Abstract: A design of equally loaded, under varying traffic load conditions, power amplifiers for a multibeam satellite is presented. Each output beam contains signals of only one beam corresponding to its input beam. The output beams are shaped to produce a small reduction of power at the crossover point of adjacent beams. MMIC and high Tc superconducting designs, including the design of high Tc superconducting reflector antenna, are presented.

Abstract: A train radio communication system includes a plurality of land communication equipments and a train communication equipment. The land communication equipments are arranged at predetermined intervals along a railroad on which a train travels and designed to output transmission signals having different frequencies. The train communication equipment is arranged in the train and designed to set a radio channel between the train communication equipment and one of the land communication equipments during travel of the train. The train communication equipment includes a plurality of antennas, an antenna switch, a receiver, and an antenna controller. The antennas respectively receive the transmission signals from the land communication equipments. The antenna switch selects one of the antennas. The receiver demodulates an output from the antenna selected by the antenna switch and outputs a reception signal.

Abstract: A high reliability access point for RF communications in a wireless local area network. The high reliability access point includes a central processing unit (CPU) for handling high level protocol functions and for interfacing with the infrastructure of the local area network. The high reliability access point also includes at least two wireless adapters. Each wireless adapter includes a radio, a media access control (MAC) processor for handling low level protocol functions, and at least one antenna. The multiple wireless adapters allow the access point to perform self monitoring, reduce the effects of multipath interference, reduce some occurrences of collisions at the access point and provide infrastructure backup in the event of an infrastructure failure. The access points also allow for wireless network infrastructure communication for connection of one or more remote access points to the infrastructure. A backup power supply for the access point is also shown.

Abstract: A diversity receiving apparatus includes a plurality of receivers, each of which receives a plurality of signals and includes a detector which selects and outputs a desired signal from the received signals, and a delay circuit which delays the desired signal to produce a delayed signal. A level comparator compares signal levels of the desired signals outputted from the detectors with one another, and produces an output indicating which one of the desired signals has a highest signal level. A selector responsive to the output of the level comparator selects and outputs the delayed signal produced by the delay circuit delaying the desired signal having the highest signal level. A demodulator demodulates the selected delayed signal.

Abstract: In a satellite communication system, ring-alerts are broadcast in a sequence that maximizes the time between when ring-alerts are issued in any adjacent antenna beam. Satellite power is conserved by allowing time for a subscriber unit to respond, after which subsequent ring-alerts directed at that subscriber are canceled. When a gateway receives a request for a ring-alert, the satellite and the antenna beams are identified which are currently serving the location of the subscriber unit being called. The satellite is provided a list of antenna beams and proceeds to broadcast ring-alerts directed at subscriber units within the identified antenna beams. Unsent ring-alerts are canceled when responses from the subscriber units are received.

Abstract: In a mobile cellular communication system, a base station is wired to a Local Area Network (LAN), and has wireless communication with a plurality of mobile stations. Multipath fading is substantially reduced in the system by utilizing antenna diversity techniques at the base station and each of the plurality of mobile stations. The combination of the independent operation of antenna selection diversity at both a base station and a mobile station results in the selection of the best propagation path between the two stations.

Abstract: A diversity receiver (200) recovers clock information from different versions (301, 302) of a transmitted signal (106). The diversity receiver (200) receives the different versions (301, 302), converts the versions (301, 302) into samples (307, 317) via a common sampling clock (309). The receiver (200) then correlates the samples (307, 317) with like synchronization patterns and uses clock information from the received version (307 or 317) which gives the greatest correlation output signal (504, 506) for data detection in one of two detectors (323, 326). The choice of detectors (323, 326) is determined by the diversity receiver (200) by counting the total number of bit-differences output by detectors (323, 326) over a predetermined time period and comparing the total bit-differences with a number represented by a threshold signal (330).

Abstract: Frequency reuse and data coding methods for use in a high data rate satellite communication system. The frequency reuse method provides for dual polarization and spatial reuse of transmit and receive beams to provide for a twelve-fold increase in the effective bandwidth and number of users that may be supported by the system. Transmit and receive antennas provide multiple, interleaved transmit and receive antenna beams. Digital input data at a source user terminal is coded and transmitted from a source user terminal on one of the plurality of receive antenna beams. The received data is demodulated and is routed so that it may be transmitted to a destination user terminal. The data is then remodulated, multiplexed, and transmitted to the destination user terminal on one of the plurality of transmit beams. The transmitted data is decoded at the destination user terminal to produce the output data.

Abstract: A universal matched filter integrates previously individualized communication hardware in an avionic suite into a single piece of digital hardware. Characterization of the individual processing functions required within an avionic system such that they lend themselves to common hardware processing allows the avionic suite to be designed with a minimum set of circuit elements, each which may be used for more than one communication mode.

Abstract: An RBDS compatible receiving method and system are provided. A broadcast receiver is tuned to a selected broadcast frequency. A first of two RBDS receivers operates in a locked mode to receive RBDS data associated with the selected broadcast frequency. Simultaneously, the second of the two RBDS receivers operates in a scanning mode to scan RBDS data associated with all broadcast frequencies. Match criteria corresponding with one or more categorical portions of RBDS data is compared with the RBDS signal associated with each broadcast frequency scanned by the RBDS receiver operating in the scanning mode. Each time a match occurs, the broadcast receiver can optionally be switched from the selected frequency to the broadcast frequency on which the match occurred while the first and second RBDS receivers switch operating modes.

Abstract: A channel selector for selecting one from among a predetermined number of received signals (e1 . . . en), and which may be used in a mobile radio system to improve the radio traffic between a mobile and a central station. The channel selector includes a summator for summing the received signals in accordance with respective weight factors (G1 . . . Gn), and an evaluation circuit for determining the weight factors on the basis of an evaluation of a characteristic, such as channel quality or signal energy, of the received signals.

Abstract: In the booster (20) of a cellular radio telephone (20) the diversity reception is arranged so that the quality, e.g. the level, of the received and amplified (Rx1, Rx2) signal is detected (A1, A2), the better signal is selected by a logic (DP), and the selected better signal is connected (SWb) to the connection (C1) of the cellular radio telephone's antenna cable (AC). The arrangement includes a circuit (TF, DP) for receiving timing information from the cellular radio telephone in order to synchronize the operation of the cellular radio telephone and the booster.

Abstract: The invention relates to switchable band filter apparatus for switching signals on-board a satellite, enabling signals of different and unforeseeable bandwidths to be switched between multiple input ports and multiple output ports. The invention also provides various payload architectures using such apparatus. Finally, the invention provides methods of implementing such apparatus and architectures for performing transparent switching of signals on-board a satellite.