Abstract: A novel improved frequency re-use planning which allows the most efficient bandwidth utilization and a larger coverage area in a wireless communications network utilizing translating repeaters is described. The wireless communications network has an available radio frequency bandwidth divided into a number of radio frequency communication channels. The channel assignments according to the frequency re-use plan described by this invention makes possible to achieve larger service coverage area using one or more base transceiver system, and efficient utilization of the limited bandwidth allocated to the network. According to the inventive frequency re-use planning, two adjacently located frequency channels are utilized while still meeting the signal isolation requirement between the adjacent channels by assigning the adjacent channels to cells that are remotely located from each other.

Abstract: Repeater apparatus for conveying a radio-frequency (RF) signal into an environment closed-off to the RF signal, including a master transceiver unit having a master port which receives the RF signal, a local oscillator (LO), which generates a LO signal at a LO frequency, and a frequency divider which divides the LO frequency of the LO signal by an integer to produce a divided LO signal. The master transceiver unit also includes a master mixer coupled to the master port and the divider which generates an intermediate-frequency (IF) signal responsive to the RF signal and the LO signal.

Abstract: A transmission system (10). The transmission system communicates data to a number of subscribers (14a, 14b). The transmission system includes a transceiver (12) that has a number of highly directional antennas (28). A number of digital repeaters (16a, 16b, 16c) are disposed in a geographic region serviced by the transceiver. The repeaters include a sectorized antenna that communicates with subscribers in a number of sectors of the geographic region of the repeater. The repeater also includes an upstream demodulator/modulator circuit (19). The upstream demodulator/modulator circuit demodulates data from signals from subscribers that were modulated with a first modulation technique, and generates a re-modulated signal with the data using a second modulation technique.

Abstract: The present invention provides an economic optical conversion relay amplification system avoiding a beat noise in an uplink line of an optical transmission line of multibranching and multinode multiplexing type.

Abstract: A contents server fault monitor periodically detects the status of operation of contents servers. Information about the status of operation of the contents servers detected by the contents server fault monitor is held in a server operation database. When an inactive contents server has been detected through look-up of the operation status information, a service menu is prepared that is a list of services which can be provided by active contents servers. Upon a request for the acquisition of a service from a portable terminal, the prepared service menu is sent to the portable terminal. By virtue of this construction, prior to the connection of a portable terminal to a network, a service menu, which indicates only services of contents servers which can provide services, can be previously presented to the portable terminal. That is, a repeater can be realized which, prior to a request for access from a portable terminal, can previously notify the portable terminal of fault information.

Abstract: A direct conversion circuit for radio frequency signals is disclosed. The circuit includes a pair of quadrature related mixers, a phase shift unit, and a local oscillator. The pair of quadrature related mixers is coupled to a radio frequency signal input port for mixing down a radio frequency input signal. The phase shift unit is in communication with at least one of the pair of mixers for phase shifting a local oscillator signal. The local oscillator produces the local oscillator signal. The local oscillator includes a non-integer frequency multiplier for multiplying the frequency of a first voltage controlled oscillator signal by a non-integer value to produce the local oscillator signal.

Abstract: A carrier changing apparatus in a mobile telecommunication system for generating a dummy frequency assignment signal for repeating a frequency conversion or providing a hard hand off based on a traffic signal is provided. In the carrier changing apparatus, a transmitting carrier changer transmits an input forward traffic signal having traffic and overhead information and generates a forward dummy frequency assignment signal based on the forward traffic signal. A receiving carrier changer receives and outputs a reverse traffic signal having traffic and overhead information from a mobile station and generates a delayed reverse traffic signal based on a reverse dummy frequency assignment signal from the mobile station.

Abstract: A system is provided for detecting the presence of an FM-modulated audio signal from an auxiliary source, and operating a switch to provide that audio signal to a tuner in lieu of the radio frequency signal received at the tuner antenna. The tuner can be a vehicle tuner. The system also comprises a modulator unit for modulating the audio signal and an output plug for insertion into a cigarette lighter receptacle or power receptacle of a vehicle. A radio frequency transmission line, such as a coaxial cable, connects the cigarette lighter receptacle or power receptacle to the vehicle battery and to an antenna switch unit and transports both DC power and the FM-modulated audio signal. The antenna switch unit comprises switched inputs for the vehicle antenna and the output from the modulator unit, and a radio frequency signal detection device for detecting when the FM-modulated audio signal is present. The antenna switch unit provides the output from the modulator unit to the tuner whenever it is detected.

Abstract: The present method for reducing latency in satellite communication includes the steps of applying, at a first earth terminal, a discriminator to user data. The discriminator delineates action data and forward data, thereby forming delineated user data. The action data represents data to be processed on board a satellite, while the forward data represents data to be forwarded through the satellite without processing. At the satellite, the delineated user data is partitioned into the action data and the forward data. The satellite then processes the action data to form processed action data and transmits, if necessary, the processed action data from the satellite. During processing of the user data, the satellite may generate result data in response to the action data and may transmit the result data alone or appended to the processed action data. Furthermore, the satellite may store a world model in a memory onboard the satellite.

Abstract: An analog transponder processor for use in a multibeam satellite receiving input beam signals and transmitting output beam signals has an input switch matrix, channel processors, and an output switch matrix. The input switch matrix power divides input beam signals into sets of input beam signals. The channel processors each receive at least one input beam signal from the input switch matrix. The channel processors filter the input beam signals into channel signals. Each of the channel signals corresponds to a respective channel of the input beam signals. The channel processors change the frequency of at least one channel signal such that the at least one channel signal corresponds to a different channel than the respective channel of the input beam signals. The output switch matrix combines the channel signals into output beam signals.

Abstract: A technique for collectively setting a factory mode of operation of a monitor offers adjustments or modifications for particulars of mode data to meet user requirements, by transmitting a set of factory mode timing data from an external controller to an electrically erasable programmable read only memory using a serial interface data communication. A factory mode data transmission process includes the steps of transmitting a start data signal to a microcomputer in a monitor when a storage key input is fed to the external controller, repeatedly sending the timing data until a mode end signal is input and sending a mode end data to the microcomputer when a mode end signal is input. In addition, a factory mode data receiving process includes the steps of sending back the start data received to the external controller, storing mode timing data received into a factory mode address reserved in a memory in the monitor and ending the reception of mode timing data when mode end data is inputted.

Abstract: A novel mobile satellite communications technique for hand-held terminals includes a satellite system having a plurality of individual satellites all in communication with a ground telecommunications hub. A signal processed by the ground telecommunications hub is radiated through multiple paths to a plurality of the individual satellites in the satellite constellation simultaneously. The radiated signal is then re-radiated by the plurality of individual satellites to a mobile satellite terminal that receives the re-radiated signal from the plurality of individual satellites simultaneously such that the same frequency spectrum may be re-used by another mobile user.

Abstract: An adapter and signal transmission cables for hands-free telephone system including a mobile telephone, car audio equipment such as a cassette recorder and a mobile telephone adapter. The mobile telephone adapter includes an adapter body, which can be pushed inside the cassette recorder; a hands-free microphone; a first signal transmission cable for connecting the adapter body and the mobile telephone; and a second signal transmission cable for connecting the hands-free microphone and the mobile telephone. The adapter body has a housing that resembles a cassette tape externally and a magnetic recording head installed inside. One end of the first and second signal transmission cables are joined together and connected to a plug, and the plug is capable of plugging into the voice input/output socket of the mobile telephone. When the mobile telephone picks up incoming voice signals, the signals will be transmitted via the adapter to the cassette recorder, which is then broadcast out through its loudspeakers.

Abstract: A system for transporting radio frequency (RF) signals across a RF network comprises a central transport unit and a remote transport unit. The frequencies of at least some of the RF signals to be transported hop in accordance with predetermined hopping sequences. The central transport unit uses the hopping sequences to convert the hopping frequencies into fixed frequencies for efficient transport through the RF network. The remote transport unit uses the hopping sequences to convert the fixed frequencies back to the original hopping frequencies. The transport system is also capable of reverse operation in the direction from the remote transport unit to the central transport unit.

Abstract: A cellular telephone system for use in an aircraft (12) comprises a plurality of user terminals distributed throughout the seating array, each group of terminals being connected through short cables to an optical/RF transducer (30) which is linked through an optical fibre array (50) to a further transducer (26) connected by short cables (27,28) to a Base Transceiver Station (22).

Abstract: A multi-beam DBS satellite system capable of providing spectrally efficient regional programming includes at least one DBS satellite having a repeater connected between multiple uplink antennas and multiple downlink antennas. The repeater has a switching processor and a formatting processor. The switching processor includes circuitry for filtering individual channels of information from the uplink frequency division multiplexed (FDM) beams received at the uplink antennas, and also includes circuitry for switching the channels of information to form a set of switched channels. These switched channels are then combined and routed to the formatting processor. The formatting processor converts the switched FDM information into a combined digital TDM signal that preferably corresponds to the DVB standard.

Abstract: In order to locate a transponder in a roadway there are first and second antenna arrays at spaced locations. Each array is associated with a switching control which causes the array beam to step through a series of beams. The signal developed in each beam is converted to a digital result. The strongest beam from each array may be determined and the location of the transponder at the intersection of the two strongest beams.

Abstract: A mobile satellite communication terminal capable of performing satellite communication both indoors and outdoors. In an indoor mode, the mobile satellite communication terminal includes an indoor terminal for carrying out transmission or reception of a signal through a ground radio link and a repeater terminal installed in such a location that the repeater terminal can get an unobstructed view of a satellite for carrying out transmission or reception of a signal through a satellite communication link. In an outdoor mode, an antenna of the indoor unit is replaced by an antenna for the satellite communication link, whereby the indoor terminal can be used as an outdoor terminal.

Abstract: A bandwidth management system for a remote repeater network for modifying a first signal to create a second signal within the bandwidth of a communications link, transferring the second signal across the communications link, and reconstructing the first signal at the remote end of the communications link. The bandwidth management system featuring several mixing modes for performing the signal conversion and reconstruction. The system offering a calibration feature to correct for phase distortions introduced in reconstruction of the original signal. The calibration feature incorporating signals from a global positioning satellite system for reconstruction.

Abstract: A converter for a satellite signal receiving antenna, comprising a input terminal for inputting a signal in a frequency band other than the output frequency band of the IF signal converted from the satellite signal, and where the IF signal and signal from the input terminal are mixed by a mixing circuit, and output through a coaxial cable from the IF output terminal.

Abstract: Control circuitry and an associated method for a modified-user, wireless communications system, such as a cellular communication system wherein groups of mobile transceiver units are positioned to travel together. Circuitry is positioned to travel together with the group of mobile transceiver units and to generate common control requests to control operation of the entire group of mobile transceiver units. When embodied in a cellular communication system, a common hand-off request is generated for the entire group of mobile transceiver units, obviating the need for each transceiver unit to independently generate a hand-off request. If a mobile transceiver is operable pursuant to an air interface standard dissimilar to a fixed-site transceiver with which communications are to be effectuated, a converter converts communication signals so that the communication signals can be communicated therebetween.

Abstract: A paging repeater (22) receives (152) a paging signal (30) transmitted (138) by a low-earth orbit satellite (24) while compensating (150) for Doppler effects, modifying (156) the paging signal (30) to produce a repeat signal (40), and transmitting (166) the repeat signal shifted in both the time and frequency domains so as to preclude the generation of interference. A pager (28) receives a paging signal (30) directly from the satellite (24) while compensating (108) for Doppler effects whenever the pager (28) is unshadowed with regard to the satellite (24), or receiving a repeat signal (40) from a paging repeater (22) whenever the pager (28) is shadowed with regard to the satellite (24).

Abstract: An accessory apparatus for mobile radio telephones, particularly those used in cellular networks, permits utilization of the full communication range capability of a vehicle-mounted cellular radio telephone by a cordless portable handset remote from the vehicle. The apparatus includes a plug-in adapter unit located in a vehicle and interconnected between the existing handset and transceiver of the vehicle-mounted radio telephone. The adapter unit includes a first, resident, down-link transceiver operating at radio frequencies outside of the cellular frequency band, and adapted to receive demodulated audio and/or data signals from the resident cellular transceiver, and retransmit the signals via a low-power modulated down-link RF carrier signal to a portable remote cordless handset/transceiver.

Abstract: A mobile communication system having a base station and a mobile station, provided with indoor and outdoor antennas in different locations of a building structure that substantially prevents penetration of electromagnetic radiation. A communication unit is connected between the indoor and outdoor antennas. The communication unit is arranged to detect a signal received at the indoor antenna from the mobile station while the mobile station is communicating with the base station, determines that the mobile station is entering the structure when the detected signal exceeds a predetermined reference level and establishes a radio link between the outdoor antenna and the base station and a circuit between the indoor and outdoor antennas and commands the mobile station to establish a radio link to the indoor antenna. The radio link established between the mobile station and the indoor antenna uses forward and reverse channels that avoid interference with other mobile stations.

Abstract: A multiple address radio network in which there is a central station and remote radio sites. The central station transmits control and data acquisition signals to the radios at the remote radio sites and the radios at the remote radio sites transmit to the central station acquired data. Each remote radio has an automatic frequency calibration circuit for adjusting its associated remote radio to reduce frequency offset between the radio frequency carrier transmitted by the remote radio and the radio frequency carrier transmitted by the central station by adjusting the temperature compensated crystal oscillator of the automatic frequency calibration circuit. Toward this end, a microprocessor of the frequency calibration circuit detects and measures the offset frequency and controls a digital potentiometer for adjusting the temperature compensated crystal oscillator.

Abstract: A digital cellular radio communication system having a remote repeater is provided. The communication system includes a central communication site which: transmits and receives signals in a first radio channel assigned according to a cellular communication system channel reuse plan, transmits signals to and receives signals from a cellular communication network unit, and digitally processes received signals for subsequent transmission in the first radio channel or to the cellular communication network unit. The communication system further includes a remote communication site, substantially remotely located from the central communication site, which: receives a signal in either the first radio channel or a second radio channel assigned according to the cellular communication system channel reuse plan, channel shifts the received signal between the first and the second radio channels, and transmits the shifted signal in the other of the first and the second radio channels.

Abstract: In a wireless communication system, a base unit transmits outgoing TDM signals within a base transmission coverage area at a first frequency. Repeaters in the base coverage area receive the outgoing signal and retransmit it within respective repeater coverage areas at respective frequencies, maintaining the same time slot orientation in TDM format. Several levels of repeaters form a hierarchy covering an expanded range. Remote subscriber units located in a coverage area receive the strongest outgoing frequency signal from a repeater/base unit in a time slot assigned to that unit for a particular call, which time slot is maintained for that call through successive levels of repeaters. Incoming TDMA signals from remote units use the same time slots used in received outgoing signals. The base unit transmits outgoing signals and receives incoming signals at the same frequency, but at different times.

Abstract: A multichannel radiotelephony system provides two way cordless communications with a plurality of multichannel transceivers portable within a coverage area comprised by a plurality of cells, each associated with a base station and antennas, such as to permit channel frequency reuse in cells within the coverage area. For at least part of the coverage area, the locations of the antennas within the cells and the locations of the base stations are independently mapped, the antennas being associated with active antenna systems and the active antenna systems being connected to the base stations utilizing broadband transmission by means of a fixed bi-directional signal distribution network. The network is connected to the base stations and the antenna systems through suitable interfaces incorporating frequency translation so that available frequency bands in the signal distribution network which will normally be shared with other services, may be utilised. Plural base stations may be co-located.

Abstract: A multiple channel radio frequency repeater has a receive port for receiving an input signal from a first antenna and a transmit port for transmitting a frequency shifted output signal to a second antenna. An input bandpass filter is located at the input port. A low noise amplifier follows the input bandpass filter for amplifying all signals within the input bandwidth. A plurality of channel filters divide the input signal into a plurality of channel signals. A local oscillator generates a local oscillator (LO) signal. There is a mixer corresponding to each channel, each mixer has an input port, an output put port and an LO port. The LO port is coupled to the local oscillator. An Automatic Gain Control (AGC) amplifier is between each channel filter and each mixer for adjusting the channel signal level to the mixer input port to assure that each mixer has the same level amplified channel signal.

Abstract: An apparatus and method for use in receiving radio frequency (RF) signals having varied frequency bands from a n-sector base station antenna, and converting the RF signals to intermediate frequency (IF) signals for allocation to all available receiver radio channels. By employing a combiner and power splitter/divider, the IF signals from the converters in each sector of the receiver can be accessed by every receiver radio channel. Accordingly, remote communications users placing calls in high traffic sectors will have access to all available radio communications channels.

Abstract: A frequency conversion apparatus comprising a sampling circuit for receiving a first intermediate frequency signal extracted from an input signal and having a predetermined intermediate frequency and a predetermined band width and sampling the first intermediate frequency signal in accordance with a predetermined sampling frequency signal, to output a second intermediate frequency signal, and a sampling signal generator for outputting the sampling frequency signal to the sampling circuit, the sampling frequency signal having a frequency determined so that an integer multiple of not less than three times the sampling frequency is outside a frequency range of the input signal.

Abstract: A repeater for use with Time Division Duplex (TDD) communications such as CT2 delivered over mains electricity cables. The repeater is coupled to a mains cable via a branch (the cable is not broken) and in alternate TDD phases converts signals from f.sub.1 .fwdarw.f.sub.2 or f.sub.2 .fwdarw.f.sub.1 and amplifies them. A clock signal to control timing of the conversion step is derived from a dedicated channel, a tone, or a call in progress. A regenerator function may be combined with the repeater.

Abstract: An SMR repeater is made agile by adding a microprocessor controlled frequency selection circuit to enable the repeater to operate on any one of several available frequencies in a band. For dispatch service, the output of the repeater is switched to a power amplifier feeding an omni-directional antenna. The repeater scans several frequencies sequentially. If a signal is detected, scanning is halted to provide repeater service, after which scanning is resumed. The frequency agile repeater is coupled to an antenna system having a narrow beam which can be steered electronically. A control computer scans the azimuth of the beam. The computer divides a service area into a plurality of cells extending radially from the antenna system and assigns channels as needed to service a subscriber. More than one cell can be on the same frequency without interference.

Abstract: A mobile radio network comprises a base transceiver station for transmitting and receiving radio signals to and from mobiles on different basic frequencies and a radio booster for receiving, amplifying and retransmitting radio signals to and from at least one shadow area. To cover the shadow areas a radio signal received by a radio booster from the base transceiver station on a basic frequency is retransmitted to a mobile station on a translated frequency different from the basic frequency and associated with the latter by a translation law. This law is such that, firstly, each of the basic frequencies is either associated with at least one translated frequency or is not associated with any translated frequency and, secondly, the difference between the value of a translated frequency and the value of the associated basic frequency is not the same for all the translated frequencies.

Abstract: For exchange of information between an earth-station and a satellite in geostationary orbit, information signals addressed to the satellite are transmitted from the earth-station, and information signals from the satellite are received at the earth-station. Signals addressed to the satellite and the signals from the satellite have a common first carrier frequency. Signals addressed to the satellite are transmitted to an intermediate satellite with an angular offset from the satellite in geostationary orbit. The intermediate satellite retransmits signals laterally to the geostationary orbit satellite on a second carrier frequency different from the first carrier frequency.

Abstract: Input RF signals to a transponder, such as a communications satellite, are down converted to a lower intermediate frequency (IF) that is common for each different channel. The channel signals are all processed at the common IF, and then up converted to different respective transmission frequencies. This allows for a down conversion/signal processing/up conversion unit design that is the same for each channel (except for frequency and gain values), and facilitates the use of inexpensive available standard components as well as low bandwidth channel filters. An improved phase noise cancellation phase lock loop (PLL) is preferably used to generate tuning signals used in the up and down conversion processes. The PLL includes two loop mixers, with the down and up conversion mixing signals taken respectively from the inputs to the first and second loop mixers. The first and second loop mixers receive mixing signals at frequencies (T-R) and (T-IF-N.multidot.

Abstract: A method and system for providing a digital wireless local loop for use by a wireless transceiver, e.g., a portable handset, in an indoor environment utilizing an outdoor base transceiver. Upon determining that the portable handset is located in an outdoor environment, the base transceiver and the portable handset communicate over one of a first plurality of frequencies. The outdoor portable handset is prohibited from transmitting and receiving signals over frequencies other than the first plurality of frequencies. Upon determining that the portable handset is located in an indoor environment, the base transceiver first transmits the communication signal to a first converter at one of a second plurality of frequencies different from the first plurality of frequencies. The first converter then converts the frequency to a predetermined conversion frequency different from the first and second plurality of frequencies.

Abstract: A repeater system in a communication system including a base station and a mobile unit provides a communications link between the base station and the mobile unit when the mobile unit is located in an environment that is substantially closed off to high radio frequency communication between the base station and the mobile unit. The repeater system has a first linear two-way frequency converter including a high frequency port for two-way coupling to the base station and a low frequency port for two-way coupling to a low frequency signal that is capable of distributing radio frequency power through the closed environment. The low frequency port is connected to a cable which propagates and receives low radio frequency power within the closed environment.

Abstract: A satellite switching network disposed to operate with relatively few redundant components. The high-frequency switching network with improved routing architecture (10) of the present invention is operative to convert input signals received over a plurality of receive channels into output signals to be carried by a plurality of transmit channels. An arrangement of receiver networks 104, 106, 108 and 110 converts the input signals to a plurality of intermediate frequency (I.F.) signals. The I.F. signals are routed to a set of synthesized downlink transmitter networks 186, 190, 192, 194 by a switch matrix 126. Each synthesized downlink transmitter generates signal energy over a set of downlink channels in response to the I.F. signals supplied thereto.

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: The present invention provides passive networks which act as the host to nonlinear and parametric interactions, with energy inputs to said networks being caused to "bleed off" auxiliary, and time-delayed conditioning flows resulting in phase modulations to the main input and which achieve, e.g., RF phase conjugation with cancellation of the noise modulation after two-way passage of beams between transmitter and receiver and when used in duplex arrangements. Also, passive networks for noise reduction in communications transmission due to conditioning of electromagnetic fields in higher order group symmetry form. Because a transmitted wave from a network of the present invention is in higher-order group symmetry form, and fields of such higher-order symmetry have a low probability of occurrence naturally, then environmental noise, which is of lower group symmetry form (usually, U(1) symmetry) and has a high probably of natural occurrence, will be excluded from a receiver matched to higher-order symmetry waves.

Abstract: An accessory apparatus for mobile radio telephones, particularly those used in cellular networks, permits utilization of the full communication range capability of a vehicle-mounted cellular radio telephone by a cordless portable handset remote from the vehicle. The apparatus includes a plug-in adapter unit located in a vehicle and interconnected between the existing handset and transceiver of the vehicle-mounted radio telephone. The adapter unit includes a first, resident, down-link transceiver operating at radio frequencies outside of the cellular frequency band, and adapted to receive demodulated audio and/or data signals from the resident cellular transceiver, and retransmit the signals via a low-power modulated down-link RF carrier signal to a portable remote cordless handset/transceiver.

Abstract: A radio communication system having a plurality of base stations, each forming a radio zone, and a plurality of mobile stations connected to those base stations in a time-division multiplexing manner via digital radio circuitry that time-division multiplexes a plurality of time slots for those base stations, comprising at least one supervising radio transmitting station for transmitting a reference synchronizing signal to a first and a second base station of the plurality of base stations via radio circuitry, the reference synchronizing signal being used in establishing synchronous relationship between the first and second base stations, receiving section installed in each of the first and second base stations, for receiving the reference synchronizing signal from the supervising radio transmitting station via radio circuitry, and synchronizing section installed in each of the first and second base stations, for establishing synchronous time-slot relationship in the digital circuitry between those base synchr

Abstract: An automatic repeater station, sometimes called a relay system, is disclo. The relay system receives signals, preferably at one band of frequencies, then filters and restores their inherent information, and finally transmits the restored information, preferably at another band of frequencies. Unlike the prior art systems utilizing transceivers and electronically tunable filters, the present invention uses separate receivers and transmitters and is devoid of electronically tunable filters.

Abstract: A transponder includes a receiver for receiving a radio interrogation signal. The transponder also includes a phase locked loop decoder for deriving a reference signal from the received interrogation signal, and a radio transmitter for transmitting a transponder reply signal. The phase locked loop has an output which feeds the AC reference signal to the transmitter. The transmitter includes a frequency doubler which generates a transmitter radio frequency at double the frequency of the reference signal. The transmitter radio frequency is therefore controlled by the radio frequency of the interrogation signal. The phase locked loop includes a divide-by-N counter, where N is a predetermined integer parameter. The parameter N determines the derivation of the reference signal frequency from the interrogation signal frequency.

Abstract: An optical radio system includes a host device, an end device, and a repeater. The host device and the end device communicate with each other via the repeater by use of optical radio. The repeater includes a section for receiving a first light signal from one of the host device and the end device, a section for converting the received first light signal into a first electric signal, a section for frequency-converting the first electric signal into a second electric signal, and a section for generating a second light signal in response to the second electric signal and transmitting the generated second light signal. The repeater also includes a section for demodulating one of the first electric signal and the second electric signal into a baseband signal, a section for detecting a quality of the baseband signal, and a section for enabling transmission of the second light signal only when the detected quality of the baseband signal is equal to or greater than a predetermined quality.

Abstract: Cordless antenna apparatus for determination of the location of an observer and/or of the time of observation by use of a Satellite Positioning System (SPS), such as the Global Positioning System or the Global Orbiting Navigational Satellite System. In each embodiment, the apparatus includes a Smart Antenna device and a display unit, connected by a wireless link. In a first embodiment, the Smart Antenna device includes: an SPS antenna to receive the SPS signals; an SPS signal frequency downconverter; an SPS signal processor to receive antenna output signals and to determine at least one of the present location of the SPS antenna or the time of observation; a transmitter to receive processor output signals and transmit these signals to the display unit; and a power supply.

Abstract: Communication systems (101, 102) having dedicated communication resources are provided with receivers (111, 116) that monitor the communication resources (104, 108) of other communication systems. Communications between communication units in various systems are interchanged through appropriate interaction of the repeaters and the dedicated receivers so provided.

Abstract: A multichannel communication system carries signals having a different frequency range in each channel. In order to achieve a particular output power level from each channel, an amplifier is associated with each channel to boost the signal level. For reliability, a switching arrangement switches amplifiers among the channels in accordance with a priority, or substitutes a redundant amplifier for a degraded or failed unit in a channel. The amplifier is subject to distortion at the desired output level, and is cascaded with a distortion equalizer or linearizer for reducing the total distortion. In accordance with the invention, each distortion equalizer is fixedly connected in one channel, and is optimized for the relatively narrow frequency range of that channel, rather than being switched together with the amplifier and being optimized over the total or cumulative bandwidth of all the channels.

Abstract: A frequency modulated ratio frequency broadcast network in which re-transmitting stations employ a synchronous frequency modulated booster system. Included in the frequency modulated booster system is a synchronous frequency modulated exciter for converting a frequency modulated intermediate frequency into a frequency modulated broadcast signal. The synchronous frequency modulated exciter includes phase locked loop circuits for synchronizing the re-transmitted frequency modulated broadcast signal with the frequency modulated intermediate frequency signal by detecting reference signals in the composite baseband of the intermediate frequency signal and in the composite signal frequency modulated broadcast signal.