Abstract: An apparatus for improving reception sensitivity of a public wave receiver includes power devices formed in a power supply of the public wave receiver, and a shielding plate for shielding noise generated by the power devices. A signal line for connecting an antenna used for the public wave receiver to a public wave receiver main body and a ground line are formed coaxially to each other by a shield layer.

Abstract: A method is provided for reducing a DC bias in a receiver. This method includes isolating a second circuit portion from a first circuit portion (535) and determining a second DC bias correction value for the second circuit portion that will eliminate a second DC bias at the isolated second circuit portion (540). The second circuit portion is then connected to the first circuit portion (550) and a bias-maximizing code word is generated at the first circuitry (505). A first DC bias correction value is then determined that will eliminate a first DC bias at the first circuit portion (555). The bias-maximizing code word is formed such that: a first integrated value of a first half of the bias-maximizing code word has a positive value, and a second integrated value of a second half of the bias-maximizing code word over half of the code word length has a negative value.

Abstract: A receiving device in which the shielding performance is improved to solve a pulling problem in a receiving device of a direct conversion system is provided.

Abstract: The level of the harmonics of oscillation signals for synchronous detection to be inputted to a mixer circuit for converting frequencies is suppressed low.

Abstract: Methods and apparatus are provided for an interconnect system for coupling radio frequency signals from one component to another in a RF system. The interconnect system acts as a coaxial connection. The apparatus comprises an interconnect, a dielectric sleeve, and a conductive elastomeric gasket. The interconnect has a first major surface and second major surface for providing an electrical connection. A through hole is formed in a first component. The dielectric sleeve is placed in the through hole. The interconnect is placed in the dielectric sleeve. The conductive elastomeric gasket is placed in proximity to the through hole contacting the first component and a second component. The RF system is assembled compressing the elastomeric gasket to have intimate contact with the first and second component. The intimate contact electrically connects the first and second component and an electric shield is formed around the interconnect thereby suppressing the reception and transmission of RF signals.

Abstract: A received signal level is controlled in a node used in a point to multi-point (PmP) radio-communication system having microwave time division multiple access (TDMA). Local node control is activated by an AGC in the receiving node, and simultaneously, a radio control loop is activated from the receiving node to each terminal regulating each terminal's transmitted power level. The receiving node AGC reconfigures quickly and is both accurate and stable.

Abstract: A radio frequency apparatus comprising a printed circuit board mounting an electronic component including a coil as an inductance element, a metal frame body covering this printed circuit board and connected to the ground, a lid formed integrally with the frame body, covering the inductance element mounting side of the frame body, and a leg formed by cutting and bending from the lid, having a width nearly same as the width of the coil, in which the leg is disposed closely to the coil.

Abstract: An enclosure part in the vicinity of a receiver part or an enclosure part to which a user brings its head close during a call is formed out of a nonconductive material of resin or the like, and an enclosure part being lower than the enclosure part of the nonconductive material has an electric conductor.

Abstract: Disclosed is a method and apparatus of transmit diversity that is backward compatible and does not significantly degrade performance in additive white guassan noise (AWGN) conditions using a transmission architecture that incorporates a form of phase sweep transmit diversity (PSTD) referred to herein as biased PSTD. Biased PSTD involves transmitting a signal and a frequency swept version of the same signal over diversity antennas at different power levels. By transmitting the two signals at different power levels, the depths of nulls normally seen in AWGN conditions when PSTD is utilized is reduced and performance degradation in AWGN conditions is mitigated.

Abstract: A system of data servers, organizing software and applications enable mobile users communicating through advanced wireless handheld devices to access a wide array of information on the Internet and in databases. The system incorporates acceleration and compression techniques, selective caching, and data-mining technology to deliver a variety of data types to the handheld at speeds many times faster (up to 20×) than it would have without the present system. Security measures are implemented at the handhelds and servers, as well as at partner sites to facilitate secure E-Commerce transactions. Direct connections to wireless networks allow a significant portion of the communications to by-pass slower wireless modems. The use of high-speed paths through the Internet allow wireless data communications across incompatible wireless standards. A central database expeditiously and in a format targeted to the handheld.

Abstract: An apparatus and method for shielding an operator from electromagnetic fields emitted from an antenna in a portable communication device. A plurality of active shields are placed between the operator's earpiece and the antenna to dampen the effects of the electromagentic fields. The active shields are coupled to adjustment circuits which may include variable gain amplifiers and phase couplers to offset the antenna signal.

Abstract: A digital radio stores advertisements for substitution during a broadcast for a bumpable advertisement within the broadcast. Upon detecting a bumpable advertisement within a predetermined broadcast period, the digital radio checks for higher priority stored advertisements—such as advertisements which were broadcast when the digital radio was not tuned to the station being monitored—and substitutes advertisements according to a priority scheme. Prioritization includes whether the advertisement has been played to the listener at least once during the broadcast period, and may extend to fee-based priority enhancements and tie-breakers or to selection based upon geographic location and/or direction of travel of a vehicle in which the digital radio is located.

Abstract: Described herein is a method and apparatus for transmission that provides the performance of space time spreading (STS) or orthogonal transmit diversity (OTD) and the backwards compatibility of phase sweep transmit diversity (PSTD) without degrading performance of either STS or PSTD using a symmetric sweep PSTD transmission architecture. In one embodiment, a pair of signals s1 and s2 are split into signals s1(a) and s1(b) and signals s2(a) and s2(b), respectively. Signal s1 comprises a first STS/OTD signal belonging to an STS/OTD pair, and signal s2 comprises a second STS/OTD signal belonging to the STS/OTD pair. Signals s1(b) and s2(b) are phase swept using a pair of phase sweep frequency signals that would cancel out any self induced interference. For example, the pair of phase sweep frequency signals utilize a same phase sweep frequency with one of the phase sweep frequency signals rotating in the opposite direction plus an offset of ? relative to the other phase sweep frequency signal.

Abstract: A capacitively back-coupled wireless terminal (10) comprises a PCB (22) having a ground conductor (24) on one surface. A back coupling capacitor (C) is carried by the ground conductor. An elongate slot (30) is provided in the ground conductor to widen the bandwidth. An electromagnetic shield (32) is provided on the side of the PCB (22) which in use is facing a lossy dielectric in order to reduce the SAR. The shield is disposed adjacent to, but spaced from, the slot (30) in the ground conductor and the back coupling capacitor. For narrowband operation the slot may be omitted and/or the spacing between the PCB (22) and the shield (32) may be reduced.

Abstract: An improvement in the shielding design and deployment of collocated radio transceivers for high-speed wireless Internet access accomplished by increased isolation brought about by wrapping each transceiver in a shield of mild steel, enclosing collocated transceivers and associated equipment in non-reflective enclosures, and use of low loss RF coaxial cables.

Abstract: The instant invention provides a digital audio processing system that includes a mainframe chassis, a central processor card, a plurality of analog input cards, and a plurality of analog output cards for accepting a plurality of audio inputs and producing a plurality of mixed audio outputs.

Abstract: The portable telephone capable of more effectively reducing the electromagnetic energy to be radiated therefrom and absorbed by the human body during its use is provided.

Abstract: The invention relates to a method of rendering telecommunication devices ineffective by creating a substantially radio frequency radiation-free environment. An interference generating pattern is provided adjacent the environment in a position between the environment and a source of radio frequency radiation signals so as to substantially reduce, or interfere with such signals thus preventing typical operation of the telecommunications devices therein. Preferably, the interference generating pattern is provided by applying silicon carbide as a coating or as part of a building material onto a structure to reduce attenuation by at least 20 to 50 decibels. Other aspects of the invention include the building materials that have the interference generating pattern associated therewith and the substantially radio frequency radiation-free environments that are created according to the methods disclosed herein.

Abstract: The cost of a receiving unit is reduced by simplifying its structure and the receiving unit structure further reduces the unit from being influenced by noises and the like generated by the main body of the television receiver. A digital television signal receiving unit includes of a metallic case, a frequency conversion circuit housed in the metallic case for converting a frequency of a received digital television signal into an intermediate frequency signal or a base band signal and an OFDM signal processing circuit for processing either the intermediate frequency signal or the base band signal and outputting an MPEG bit stream signal. Operations of the frequency conversion circuit and the signal processing circuit are controlled by a control signal outputted from a control circuit arranged outside the metallic case.

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

Abstract: A method and apparatus are disclosed for suppressing interference in a radio frequency (RF) communication system using active shielding techniques. An opposing neutralizing signal is applied to actively neutralize stray signals in a microwave communication environment. An interfering or stray signal is detected using a sensing antenna, and the opposing neutralizing signal is generated in response thereto. The opposing neutralizing signal is applied to a signal neutralizing shield to shield any desired components or devices. The opposing neutralizing signal is approximately 180 degrees out of phase, and of equal magnitude to the detected interfering signal. A phase shifter/null feedback device receives the detected stray signal, if any, and adaptively adjusts the phase and magnitude of the opposing neutralizing signal. In one embodiment, the phase shifter/null feedback device includes an integrator that generates a DC value that is proportional to the energy of the interfering signal.

Abstract: An up-converter section and a down-converter section are contained in separate respective chassis. The up-converter section and the down-converter section are linked by an IF link section having a coaxial shielding structure. As such, a high-quality Up/Down tuner can be provided which is able to reduce the mutual influence of up-converter and down-converter local oscillator circuits and the entry of external noise, without increasing the size of the Up/Down tuner.

Abstract: The present invention provides a cellular phone comprising: a housing having front and rear casings wherein the rear casing comprises a metallic layer coated on an inner side of the rear casing for insulating electromagnetic radiation, a circuit board installed in the housing having a board surface and an antenna connector installed at an upper end of the board surface, an antenna installed at an upper end of the housing and electrically connected with the antenna connector at the upper end of the board surface for receiving or emitting electromagnetic radiation, and an elastic conductor.

Abstract: In a foldable portable telephone, a shield box provided within an upper casing is connected via a flexible cable to an output terminal of a transmitting circuit provided within a lower casing, and the shield box is used as an antenna. Thus, compared to the conventional case where a rod antenna is provided at an upper end of the lower casing, variation in gain dependent on a state of the user's hand holding the portable telephone is lessened.

Abstract: A method for practically loading a small-sized and compact transmission or receiving module for an optical link in which interference between a receiving circuit and a transmission circuit can be prevented, high speed and high quality communications with a high S/N ratio can be carried out, and generated heat at the IC or the like can be discharged efficiently to a surrounding atmosphere, wherein at least a pair optical fibers 2 are installed at a fiber installing part 4, each light emitting element 5 and light receiving element 6 is arranged in a direction of an optical axis each of transmission optical fiber and receiving optical fiber installed at the fiber installing part, a first board 10 connected to root portions of the lead terminals of the light emitting element and the light receiving element is integrally formed with a second board 12 and a third board 14 respectively connected to both opposing ends of the first board through a flexible board, and the second board and the third board are folded at

Abstract: A vehicle surroundings monitoring device capable of performing distance measurement as desired even in a short-distance range to provide unerring alarm information to a driver. The monitoring device for monitoring surroundings around a vehicle has a transmitting antenna provided in a door mirror assembly of the vehicle to radiate transmitted waves through a mirror surface of the door mirror, and a receiving antenna provided in the door mirror assembly to receive reflected waves from an object existing near the vehicle through the door mirror surface. The monitoring device also has a stray electric wave limiting member for reducing electric wave components straying from the transmitting antenna into the receiving antenna.

Abstract: An improvement in the shielding design and deployment of collocated radio transceivers for high-speed wireless Internet access accomplished by increased isolation brought about by wrapping each transceiver in a shield of mild steel, enclosing collocated transceivers and associated equipment in non-reflective enclosures, and use of low loss RF coaxial cables.

Abstract: A double super tuner for receiving television signals from conventional broadcast, CATV, satellite broadcast, and HDTV. A first frequency converter converts an input high-frequency signal in a first intermediate frequency band signal based on a first local oscillator signal. The output of the first frequency converter is band-pass filtered by a dielectric filter. A second frequency converter converts the output of the dielectric filter into a second intermediate frequency band signal based on a second local oscillator signal.

Abstract: A light guide/shield assembly for use with a circuit board includes an upstanding, electrically conductive shield wall adapted to be mounted on and electrically grounded to the circuit board. The shield wall defines an opening. A light guide member including a light transmissive guide body and an electrically conductive shield layer is mounted on the shield wall such that the shield layer overlies the opening. The light guide/shield assembly thereby defines an RF shielded chamber. The light guide/shield assembly may further include an LCD panel mounted on the light guide member. An RF shielded PCB assembly includes a circuit board including an electrical ground and the light guide/shield assembly mounted thereon.

Abstract: A CATV transceiver is provided within an RF shield enclosure. The transceiver circuit includes a diplexer, having fixed value inductors, that is coupleable to a CATV cable plant to receive an RF input signal and to transmit an RF output signal. The RF receiver is coupled to the diplexer and includes a frequency up-converter, a first frequency down-converter and a second frequency down-converter. The up and first down-converters include voltage controlled oscillators that are responsive to a control signal generated from a single oscillator crystal. The second frequency down-converter operates to provide an output signal representative of the RF input signal within a predetermined output frequency pass-band. The RF transmitter is also coupled to the diplexer and provides for the transmission of the RF output signal in response to an input signal.

Abstract: A cable modem tuner includes, in the same casing, an up-stream circuit to transmit an up-stream data signal to a CATV station, and a reception circuit for receiving a down-stream signal via a HPF that removes the up-stream data signal. The reception circuit includes a select circuit that selects a signal of a desired frequency band out of one of three frequency bands, a signal processing block including three local oscillation circuits to convert a signal of a desired frequency band into an intermediate frequency signal of a desired channel using an oscillation signal of a corresponding oscillation circuit, and a down converter with a local oscillation circuit converting an applied signal into a signal for demodulating a received signal. The down converter provides a baseband signal used to demodulate a received signal by the QAM when a digital signal modulated by the QAM is received.

Abstract: A carrier and shield arrangement, where the transceiver of a circuit board is exchangeable through the front panel of a station in the computer network. The shield physically connects to the carrier mounted on the circuit board, where the carrier receives the transceiver and electrically connects the transceiver to the circuitry on the circuit board. The shield has two walls, a cover and a panel portion which are formed of a material to block electromagnetic interference. The walls are electrically connectable to the circuit board, and a panel portion of the shield is electrically connectable to the carrier and to the front panel.

Abstract: An improved, compact, lightweight handy-phone provided with a built-in directional planar antenna is provided. The planar antenna is mounted on a portion of a high-frequency printed wiring board, and a shielding case covers the high-frequency printed wiring board with a surface of the portion exposed. A maximum linear size of the shielding case in the direction of main polarization of the planar antenna is nearly equal to half the wavelength of an electromagnetic wave to be radiated by the planar antenna.

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

Abstract: A double super tuner for receiving television signals from conventional broadcast, CATV, satellite broadcast, and HDTV. A first frequency converter converts an input high-frequency signal in a first intermediate frequency band signal based on a first local oscillator signal. The output of the first frequency converter is band-pass filtered by a dielectric filter. A second frequency converter converts the output of the dielectric filter into a second intermediate frequency band signal based on a second local oscillator signal.

Abstract: Cross-over modulation between radio frequency circuits and audio circuits is minimized in a wireless portable transceiver by locating all audio circuitry in a first section of the portable transceiver and all radio frequency circuitry in a second, separate section of the portable transceiver. In view of modality considerations in small portable transceivers, an audio signal is either radiated or received in the vicinity of the radio frequency circuitry. Isolation of the audio signal is achieved by routing this signal while in its acoustic form. Since audio signals in an electrical form are not routed around or near the radio frequency circuitry, cross-over modulation does not occur between the radio frequency circuitry and the audio circuitry.

Abstract: A communication system and method, particularly adapted for use in adaptive antenna arrays, are presented. A plurality of signals containing a desired signal, interference, and noise are received through an array of antennas connected to a base receiving station. The signal arriving at each antenna is weighted according to computations which adjust those weights as a function of received interference and noise power in an unequal manner, based on the estimation accuracy of the interference and noise, which in turn depends on factors such as interference to noise power ratios and fading rate.

Abstract: A multi-mode radiotelephone (10) includes at least one antenna (12) for transmitting and receiving RF signals within at least two frequency bands. The radiotelephone also includes a first receiver (30, 34) having an input coupled to the antenna for amplifying and down-converting RF signals within a first frequency band and a second receiver (30a, 34a) having an input coupled to the antenna for amplifying and down-converting RF signals within a second frequency band. The radiotelephone further includes a first transmitter (44, 46, 48) having an output coupled to the antenna for up-converting and amplifying RF signals within the first frequency band and a second transmitter (44a, 46a, 48a) having an output coupled to the antenna for up-converting and amplifying RF signals within the second frequency band.

Abstract: The invention provides a transceiver in which a mutual interference between the transmitting and receiving circuits can be suppressed, without a shielding plate therebetween. The transceiver comprises the first and second printed circuit boards, which are positioned face to face. Components of the transceiver are mounted on the front surfaces of the aforementioned printed circuit boards, and compose the transmitting and receiving circuits. The front surfaces of the first and second boards are respectively divided into the transmitting and receiving regions As and Bs, on which corresponding components are respectively mounted. The aforementioned regions As and Bs are so formed that they are respectively positioned face to face, then the components of the transmitting and receiving circuits are never positioned back to back, and the mutual interferences between the transmitting and receiving circuits does not occurs, even if a shielding plate is eliminated.

Abstract: A radio frequency apparatus has a tuner unit which is disposed in a tuner unit housing, and a demodulation unit which is disposed in a demodulation unit housing easily attached or removed to the tuner unit housing by a connecting device provided on side walls of the tuner unit housing and the demodulation unit housing.

Abstract: A satellite channel interface (SCI) is constituted by an analog section having a multiplexer unit and a down converter unit, and a digital section constituted by a modulator-demodulator unit. The satellite channel interface has a single printed circuit board on which all of the above units are formed. A rectangular member surrounds the analog section, and a shield cover shields an opening portion of the rectangular member. The single printed circuit board is a multi-layered board constituted by at least three conductive layers, of which the bottom two layers are grounding electrodes. The SCI does not require the terminals and cables which are otherwise necessary, can be made compact, and can be manufactured with the reduced number of processing steps.

Abstract: Shielding structures are provided for microwave circuits with substrate members and shield members which are formed from conventional substrates. The shield members are shaped and joined to the substrate members to form conductive compartments that substantially surround the microwave circuits and the compartments are closed with a conductive cover. The substrate members and shield members form parallel-plate waveguides which communicate between the compartments. The loss of these waveguides is increased with air-dielectric posts to obtain greater isolation between compartments.

Abstract: An optical transceiver unit capable of preventing any crosstalk from an optical transmitter to an optical receiver to thereby avert reduction of the reception sensitivity. The optical transceiver unit comprises a multilayer printed circuit board, a lower case for housing the multilayer printed circuit board therein, and an upper case so disposed as to cover the lower case for enclosing the multilayer printed circuit board in an assembly of the two cases. A light emitting element module and a light receiving element module are attached to one side wall of the lower case. The printed circuit board has a first region where a transmitting circuit is formed, and a second region where a receiving circuit is formed. The first and second regions are completely isolated electromagnetically from each other by a first shield plate fixed to the lower case and a second shield plate fixed to the upper case.

Abstract: In a tuner unit including an antenna input filter section, a UHF section, a VHF section, and a PLL section which are electromagnetically separated by walls, an inductor for a VHF local oscillator is disposed adjacent to the UHF section, and is electromagnetically separated by a subdivision wall from the UHF section and the VHF section.

Abstract: A first PLL 15 circuit connected to a first local oscillator 4 and a second PLL circuit 18 connected to a second local oscillator 10 are disposed in a same casing 20, and it is therefore not necessary to issue the output signal of the second local oscillator 10 or the divided output signal of the first local oscillator 4 outside of the casing 20, so that generation of undesired harmonic interference due to adverse effects of distribution thereof may be eliminated, thereby obtaining a favorable reception state.

Abstract: The present invention relates to a television tuner capable of receiving television broadcasting, CATV and satellite broadcasting. The television tuner includes a double superheterodyne tuner for receiving television signals, having an up-converter, a down-converter and a coupler for coupling the up-converter and down-converter, and the television tuner also includes a BS second mixer portion and a FM demodulator, for receiving signals from a broadcasting satellite. The double superheterodyne tuner, the BS second mixer portion and the FM demodulator are disposed in a housing, a combination of the up-converter and the BS second mixer portion is desiredly separated from the down-converter, the coupler is disposed in a space between the combination and the down-converter, and the FM demodulator is disposed in the remaining space of the housing.

Abstract: A wireless in-building RF communications system operates within a building in a microwave frequency range which is also utilized by a point-to-point microwave communication system such that frequency reuse is provided. Central modules and user modules each consist of RF transceivers and antenna systems. The wireless communication system includes a mechanism for limiting magnitude of RF signals transmitted by it from exceeding a predetermined level sufficiently small to prevent interference with the point-to-point communications system.

Abstract: A process for fabricating an electromagnetic shield for a display provides for a sheet upon which a metal mesh pattern and a border surrounding the metal mesh pattern is photo-chemically etched on the sheet. In addition, a portable radio having an electromagnetic shielded display provides for a bordered metal mesh disposed between a cover and a display.

Abstract: In a tuning circuit for AM receiver, tuning coils, oscillation coils and capacitance elements of an antenna tuning circuit, a radio frequency amplifier circuit, and a local oscillator circuit are accommodated in discrete shield casings for high frequency coils; and the discrete shield casings are disposed in a row and united with each other in the form of blocks, thereby eliminating the necessity to effect tracking adjustment.

Abstract: Transient protection unit intended for connection to signal conductors for protecting equipment connected to the conductors against EMP and EMI. The unit includes primary protection components in the form of gas discharge tubes between the conductors and earth, and secondary protection components connected after the primary protection, in the form of filter components (L,C) or the like. All the components are mounted on a circuit board (6), the printed circuit pattern of which includes contact surfaces (10) for the unearthed electrodes of the tubes (X3-X5), against which contact surfaces the tubes are mounted by clamping with the aid of a metal member (18) serving as earth conductor.