Abstract: A dual-band input transceiver block is formed to operably receive one of a 2.4 GHz radio frequency signal or a 5.0 GHz radio frequency transceiver signal in a manner that minimizes duplication of circuitry and creates a combined circuit path for RF front end input stages for much of the input stage. The embodiments include separate amplification and mixing stages whose outputs are combined by a stabilized load with circuitry for removing a common mode feedback signal. A first input section is operably coupled to receive a first local oscillation input and a first frequency band signal input. A second input section is coupled to receive a second local oscillation input and a second frequency band signal input. Outputs of the first and second input sections are produced to a stabilized load with a common mode feedback block for removing a common mode feedback signal.

Abstract: A transceiver circuit and a method in a wireless communication network are provided, where a signal power level for a signal received at the transceiver circuit is measured and compared to a predefined threshold power level. At least two groups of power amplifiers may be used, where one group is optimized for high efficiency above the predefined threshold power level, and one group is optimized for high efficiency below the predefined threshold power level. The amplifiers may be used to amplify the received signal depending on the signal power level in relation to the predefined power threshold level. The signal may then be filtered by duplex filters and forwarded to a diversity antenna or a main antenna where it is transmitted over an air interface.

Abstract: A system for tuning an impedance at a node comprises a first component associated with a first impedance when the first component is operating and a second impedance when the first component is not operating. The system further comprises a second component coupled to the first component at a node. The second component is associated with a third impedance when the second component is operating and a fourth impedance when the second component is not operating. An impedance tuning circuit is coupled to the second component at the node and operable to tune an impedance at the node based at least in part upon a plurality of the first impedance, the second impedance, the third impedance, and the fourth impedance.

Abstract: A terahertz radiation mixer comprises a heterodyned field-effect transistor (FET) having a high electron mobility heterostructure that provides a gatable two-dimensional electron gas in the channel region of the FET. The mixer can operate in either a broadband pinch-off mode or a narrowband resonant plasmon mode by changing a grating gate bias of the FET. The mixer can beat an RF signal frequency against a local oscillator frequency to generate an intermediate frequency difference signal in the microwave region. The mixer can have a low local oscillator power requirement and a large intermediate frequency bandwidth. The terahertz radiation mixer is particularly useful for terahertz applications requiring high resolution.

Abstract: To provide an antenna device adapted to interrupt jamming waves and enable cost reduction, a high-pass filter (HPF) adapted to interrupt general-use frequencies at least near a low-frequency side of a pass band intended for use is provided as a frequency selection circuit 11A on the antenna 1 side in an initial-stage LNA 2A. By setting a low-side cutoff frequency to 900 MHz, it is possible to prevent reception of frequencies in a general-use frequency band with a high frequency of use as jamming waves. That is, for example, it is possible to prevent reception of frequencies in 800 to 900 MHz band for mobile cellular telephones and higher harmonics thereof as jamming waves. Further, since an additional filter is not required in the antenna device, the circuit structure can be simplified.

Abstract: A frequency-mixing method includes a step of generating a first quadrature signal having a predetermined frequency, a second quadrature signal having a phase difference of about 180 degrees with respect to a phase of the first quadrature signal, a third quadrature signal having a phase difference of about 90 degrees with respect to the phase of the first quadrature signal and a fourth quadrature signal having a phase difference of about 90 degrees with respect to a phase of the second quadrature signal; a step of controlling a phase of the third quadrature signal and a phase of the fourth quadrature signal so as to control a linearity of a frequency mixer; and a step of down-converting a radio frequency (RF) signal using the first through the fourth quadrature signals. Accordingly, performance of a direct-conversion receiver (DCR) can be improved by employing a frequency-mixing device capable of enhancing a linearity of a frequency mixer.

Abstract: A radio-frequency signal receiver capable of enhancing reception performance includes an antenna for receiving radio-frequency signals, a first switch having an end coupled to the antenna, a filter coupled to the first switch, a second switch having an end coupled to the first switch and an end coupled to the filter, a low noise amplifier coupled to the second switch for amplifying signals received from the second switch, a frequency down converter coupled to the low noise amplifier for down-converting a frequency of signals outputted from the low noise amplifier, a signal processing circuit coupled to the frequency down converter for performing signal processing, and a control circuit for controlling the first and the second switches.

Abstract: A sub-harmonic mixer and a down converter with the sub-harmonic mixer are provided. The sub-harmonic mixer includes a differential amplifying unit, a current buffer unit, and a switching unit. The differential amplifying unit is used to amplify a radio frequency (RF) signal and employs a first resonance circuit to force a leakage signal to flow to a first voltage. The current buffer unit is used to amplify the gain of an output signal of the differential amplifying unit and employs a second resonance circuit to force the leakage signal to flow to a second voltage. Finally, the switching unit switches an output signal of the current buffer unit into a base band signal.

Abstract: A bandpass-sampling analog-to-digital demodulator (BS-ADD) is provided. A radio frequency (RF) signal is received by a junction summer, which subtracts a feedback signal from the RF signal to produce an error signal. The error signal is then bandpassed and amplified by the RF bandpass filter/amplifier. The amplified signal is bandpass-sampled by a low-resolution analog-to-digital converter, and is demodulated and converted into a high-resolution digital signal. The down converted signal is multiplied with a clock to be up-converted back to the radio frequency. The resulting multiplied signal is converted to an analog signal and fed back to the junction summer.

Abstract: A semiconductor device includes an antenna circuit for receiving a wireless signal, a power supply circuit generating power by the wireless signal received by the antenna circuit, and a clock generation circuit to which power is supplied. The clock generation circuit includes a ring oscillator which self-oscillates and a frequency divider which adjusts frequency of an output signal of the ring oscillator in an appropriate range. A digital circuit portion is driven by a clock having high frequency accuracy, so that a malfunction such as an incorrect operation or no response is prevented.

Abstract: A wideband mixer includes a core mixer having input terminals and output terminals for, respectively, receiving differential input signals and providing amplified differential output signals. A steering module is coupled to the core mixer for receiving differential reference signals and providing bi-phase modulated amplified differential output signals. The core mixer is configured to provide a value of gain between the differential input signals and the differential output signals. A bandwidth peaking network is coupled to the core mixer and includes (a) a first coil and a first resistor connected in series and (b) a second coil and a second resistor connected in series. The first coil and resistor and the second coil and resistor, respectively, are coupled to the core mixer for receiving the amplified differential output signals. The bandwidth peaking network is configured to increase the frequency bandwidth of the core mixer.

Abstract: A receiver and receiver front end having multiple independent differential inputs, multiple independent differential low-noise amplifiers, and two sets of double-balanced IQ mixers. The double-balanced mixers include cross-coupled PMOS devices that dynamically inject current at zero-crossing points to cancel out tail currents in the mixers. Also, methods of operating the above-discussed receiver and receiver front end.

Abstract: A time division duplex (TDD) wireless apparatus includes a low noise amplifier (LNA) system, at least one antenna and a transceiver system. The apparatus supports N time division duplexed channels which each have a transmit direction of transmission flow and a receive direction of transmission flow. The LNA system comprises N sub-units. Each sub-unit comprises a first circulator for connecting to a respective TX/RX feed to the transceiver system and a second circulator for connecting to the at least one antenna. The first circulator and second circulator within each sub-unit are interconnected to provide a path in one of the directions of transmission flow. The first circulator of each sub-unit is connected to the second circulator of another sub-unit to provide a path in the other direction of transmission flow. A single channel variant is also provided.

Abstract: An AM demodulator using totem pole complementary metal oxide semiconductor transistors having a feedback to provide a common gate voltage of approximately half that across the transistors in the totem pole. The AM demodulator used in a hearing assistance device and in a programmer of a hearing assistance device.

Abstract: A receiver apparatus including a main input for receiving the input signal and a first standard mixer having a first mixer input, a first local oscillator input, and a first mixer output. The first mixer input is connected to the main input and the first local oscillator input is connected to a source that provides a first local oscillator signal having a frequency close to or equal to the carrier frequency. The apparatus further including a second mixer with a second mixer input, a second local oscillator input, and a second mixer output. The second mixer input is connected to the main input and the second local oscillator input is connected to a source that provides a second local oscillator signal with an undesired sideband frequency. There are circuit for super-positioning the first output signal and the second output signal. The first local oscillator signal and the second local oscillator signal are square-wave signals.

Abstract: A system and method for providing auxiliary reception in a wireless communications system includes a wireless communications device. The wireless communications device includes a first antenna and a second antenna. The wireless communications device can, for example, establish two-way communications with a wireless communications network. The wireless communications device can also use the second antenna in at least one of a mobile assisted hand off (MAHO), a diversity antenna system and a global positioning system (GPS) system.

Abstract: A Gilbert cell mixer for a wireless transceiver includes a first stage that performs voltage to current conversions and that includes first and second transistors that are operated in a saturation region and third and fourth transistors that are operated in a triode region. A second stage communicates with the first stage and that performs frequency conversion. A biasing circuit communicates with the first stage to maintain a substantially constant input linear range over temperature and process variations.

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

Abstract: An inexpensive, high-performance, fully-integrable, multi-standard transceiver with a topology including: an active mixer, followed by a high pass filter, and a passive mixer. The input signal is modulated up, or demodulated down, using a pair of complementary, aperiodic mixing signals. The use of aperiodic mixing signals allows a fully-integrated transceiver to be built. Embodiments of the active mixer include those having electrically-adjustable performance and allowing multiple RF signal inputs. This allows the topology to be employed in multi-band, multi-frequency applications, while still providing high performance.

Abstract: Heretofore, a plurality of packages were used in a high frequency module in which a plurality of waveguide terminals were positioned resulting in problems, such as degradation of characteristics in the connection lines between packages, lower ease of assembly when mounting and connecting the connection lines, increased cost, and so forth. To solve these problems, a plurality of cavities having a part or the entire side metallized is formed in a multi-layer dielectric substrate. The multi-layer dielectric substrate is provided with a plurality of waveguide terminals, microstrip line-waveguide converters, RF lines, bias and control signal wiring, and bias and control signal pads. A high frequency circuit is mounted within the cavity and sealed with a seal and cover. This is intended to reduce the number of package, improve performance, improve fabrication, and lower the cost.

Abstract: Configuration of a connection between an even-harmonic mixer and a filter is simplified, thereby enabling size reduction. An even-harmonic mixer and a high-frequency bandpass filter are connected to each other via a transmission line, thereby forming a filter-integrated even-harmonic mixer. The length of the transmission line is set so that impedance on the transmission line side as viewed from a connection point between the even-harmonic mixer and the transmission line is approximately 0 for a frequency fLO of a local oscillation signal. This allows elimination of an open stub which is used in a conventional even-harmonic mixer and of which the line length to provide equivalent grounding for the frequency fLO is about 1 mm. Thus, the connection portion between the even-harmonic mixer and the high-frequency bandpass filter is simplified and a compact circuit layout for the filter-integrated even-harmonic mixer is obtainable.

Abstract: A method for generating phase signals includes triggering a phase register to output a binary number stored in the phase register, wherein the phase register is triggered based at least in part on a voltage signal provided by a voltage controlled oscillator. The method also includes providing an input signal to a decoder, wherein the input signal is based at least in part on the binary number output by the phase register and the decoder is operable to generate phase signals in response to the input signals. The method further includes incrementing the binary number stored in the phase register and repeating the triggering and providing steps after the binary number is incremented.

Abstract: A method for reducing frequency glitches in a digital transceiver due to power amplifier input impedance variations. According to the method, the power amplifier is switched on after the end of a prior packet reception period and before a new packet transmission begins. Instead of ramping the power amplifier gain, the method ramps the modulation signals. As a consequence, any VCO frequency transients that may result from turning on the power amplifier have an opportunity to decay before the new packet transmission is initiated. This technique effectively isolates the transmitter power amplifier from the frequency synthesizer VCO to facilitate fast switching transceiver operation.

Abstract: A method for adjusting a programmable mixer of a local oscillation module to reduce local oscillation leakage begins by determining at least one of: DC offset of an input signal of the programmable mixer and process mismatches between a first mixing stage and a second mixing stage. The method continues by determining operational characteristics mismatch between the first mixing stage and the second mixing stage based on the at least one of the DC offset and process mismatches. The method continues by generating a control signal to substantially compensate for the operational characteristics mismatch. The method continues by providing the control signal to a compensation module, wherein the compensation module modifies operational characteristics of at least one of the first and second mixing stages based on the control signal such that the operational characteristics of the first mixing stage substantially equals the operational characteristics of the second mixing stage.

Abstract: An upconverter for mixing a single-ended RF signal with a differential local oscillator signal to generate a differential IF signal, that includes a source degenerated first differential pair comprising matched first and second transistors, each having source, gate and drain terminals, wherein the gate of the first transistor receives the input signal and the gate of the second transistor receives a ground potential, and a second differential pair comprising matched third and fourth transistors, each having source, gate and drain terminals, and a third differential pair comprising matched fifth and sixth transistors, each having source, gate and drain terminals, wherein the sources of the third and fourth transistors are coupled to the drain of the first transistor and the sources of the fifth and sixth transistors are coupled to the drain of the second transistor, the gate of the third transistor is coupled to the gate of the fifth transistor and the gate of the fourth transistor is coupled to the gate of th

Abstract: A circuit is formed to steer current in and out of an inductive load in a manner that enables an amplifier to provide a plurality of gain steps without modifying an LC time constant for the circuit and, therefore, without modifying the tuning or frequency of oscillation for the circuit. A first group of MOSFETs are coupled in parallel and define the circuit current flow. A second group of MOSFETs are coupled in parallel to each other and in series to an impedance device. A third group of MOSFETs coupled to steer current in and out of the impedance device to affect the output signal coupled to one end of the impedance device. The transistors in the second and third groups of MOSFETs are selectively activated to control the amount of current that goes through the impedance device.

Abstract: A high gain, highly linear mixer includes an input section, mixing section, at least one tuning component, and at least one stand by current source. The input section is operably coupled to receive an input voltage signal and perform a linear transconductance thereon to produce an input current signal. The mixing section is operably coupled to mix a local oscillation with the input current to produce a mixed current signal. The tuning component is operably coupled to the mixing section and to convert the mixed current signal into a mixed voltage signal that function as the output of the mixer. The standby current source is operably coupled to the mixing section and provides a standby current to the mixing section.

Abstract: Apparatus, and an associated method, for acting upon data signals received at a base station of a fixed wireless access communication system. A plurality of modems are positioned at the base station, and a controller controls to which modem that a data signal, transmitted by a particular subscriber station, is applied to a particular modem. Profiles relating to channel and signal characteristics are also maintained and used by the modem during demodulation operations.

Abstract: A single chip direct conversion transceiver that includes a substrate on which a mixer unit and a local oscillator are provided as a circuit, and a positive hole formed between the mixer unit and the local oscillator and filled with a conductive plug to block signal leakage. A shield ground surface is formed above the substrate and blocks signal leakage occurring when the signals received through the antenna are input into the mixer and signal leakage occurring when the reference signal is input into the mixer from the local oscillator. A first interconnection is formed above the shield ground surface and connects the mixer unit and the local oscillator. Dielectric layers are formed between the substrate and the shield ground surface and on the shield ground surface to cover the first interconnection.

Abstract: An electronic tuner of the present invention is arranged such that between an input part of the amplifying circuit and the ground serially connected are a coil and a diode, and a capacitor is connected between the ground and a connecting part between the coil and the diode. The diode is brought into conduction when a voltage supplied from a VHF High control source is at High level, and the coil and input capacitance of the amplifying circuit makes up a gain correction circuit for improving a frequency characteristic of a received signal in a VHF High band. The diode is brought out of conduction when a voltage supplied from a VHF High control source is at Low level, and the coil and the capacitor makes up a trap circuit for improving a frequency characteristic of a received signal in a VHF Low band. This makes it possible to minimize price increase of the apparatus and to improve frequency characteristics in the VHF High band and VHF Low band.

Abstract: An aspect of the present invention provides a receiving circuit that includes a mixer configured to receive a signal and a local signal to mix the signals, the mixer configured to convert the signals into an intermediate frequency signal, an IF filter configured to filter the intermediate frequency signal outputted from the mixer, an IF amplifier configured to amplify a band of the intermediate frequency signal outputted from the IF filter, and a demodulation circuit configured to receive a signal outputted from the IF amplifier to carry out demodulation, wherein a part of the demodulation circuit is disposed outside of the receiving circuit.

Abstract: A transmission power amplifier unit of a base-station apparatus for compensating for non-linear distortion of a transmission power amplifier by feed-forward control is provided with a gain varying unit for varying gain of the transmission power amplifier unit. At start-up of the transmission power amplifier unit, a controller determines whether the base-station apparatus is in a blossoming mode or breathing mode, maximizes gain of the transmission power amplifier unit by controlling the gain varying unit if the mode is the blossoming mode and increases the gain gradually in proportion to the passage of time if the mode is the breathing mode.

Abstract: A receiver and receiver front end having multiple independent differential inputs, multiple independent differential low-noise amplifiers, and two sets of double-balanced IQ mixers. The double-balanced mixers include cross-coupled PMOS devices that dynamically inject current at zero-crossing points to cancel out tail currents in the mixers. Also, methods of operating the above-discussed receiver and receiver front end.

Abstract: A communication apparatus transmits, to another apparatus or apparatuses, a message for searching for an apparatus as a connection target by radio communication, and receives a response message from another apparatus which has received the message, thereby searching for an apparatus as a connection target. The control information setting section of the device body of a communication apparatus inputs a search range in which a station finding message reaches in accordance with designation by a user and sets it as set information. The station finding procedure section of the radio communication apparatus transmits the station finding message in accordance with a transmission power corresponding to the control information set by the control information setting section.

Abstract: The invention relates to a receiver of signals [S] received from a wireless network, said receiver working at a so-called reference oscillation frequency controlled by a so-called reference value [Vref]. Said receiver includes demodulation means [DEMO] for demodulating the received signal [S], means [EST] of estimating a mean value [MV] of the demodulated signal [SD], means [COR] of correcting the mean value [MV] of the demodulated signal [SD] to the reference value [Vref], decision means [DEC] for determining the binary values adopted by the received signal [S]. According to the invention, the estimation means [EST] include first means [ESTA] of fast extraction of a first mean value [MVA] of the demodulated signal [SD] used in decision means [DEC] during a first time period and second means [ESTB] of slow extraction of a second mean value [MVB] of the demodulated signal [SD] used in correction means [COR] and, during a second time period, in decision means [DEC].

Abstract: The invention relates to an anti-demodulator circuit which is fundamentally built up in the same way as a demodulator circuit but, instead of a bandpass filter as generally used in a demodulator, comprises a notch filter which receives an input signal comprising a useful signal and an interference signal, and generates a filtered signal. The notch filter has a center frequency which approximately corresponds to the frequency of the input signal so as to suppress at least a part of the useful signal. The anti-demodulator circuit further comprises a mixer circuit which receives the filtered signal and a phase-shifted input signal and supplies a demodulated output signal which substantially corresponds to the interference signal.

Abstract: A sensor front end for an electronic radar sensor is disclosed that provides for a lower parts count while providing technical functionality by using multifunction parts, i.e., parts that are used both in transmitting and receiving. The sensor front end includes a continuous wave signal source that functions as a signal source when the front end is transmitting a signal and as a local oscillator when the front end is receiving a signal. The sensor front end also includes a tri-mode mixer that functions as a phase-modulator and transmit switch when the front end is transmitting a signal and as a mixer/down-converter when the front end is receiving a signal. The sensor front end further includes a common aperture antenna that acts as both a transmitting antenna for transmitting a sensor signal and for receiving a reflected signal from a object.

Abstract: A triple balanced mixer has a compact size and is readily assembled. The triple balanced mixer has a planar substrate that is formed from several layers of low temperature co-fired ceramic. The substrate has a top layer, a bottom layer and inner layers. Vias extend through the substrate. A local oscillator balun and RF balun are located on the inner layers. An intermediate frequency balun is mounted to the top layer. Diode rings are mounted on the top layer. The diode rings are electrically connected to the local oscillator balun, the RF balun and the intermediate frequency balun through the vias.

Abstract: A mixer is disclosed that includes first and second transconductance modules that, in one embodiment, includes MOSFETs configured to receive a plurality of signals that are to be mixed and a selectively coupled auxiliary current source to inject an auxiliary current into the second transconductance module approximately at or near a zero-crossing point in order to reduce flicker noise and other noise introduced into an output signal during switching. Accordingly, as a first transconductance module approaches a zero-crossing, auxiliary current is injected to reduce the current produced therefrom thereby reducing flicker noise. In a differential mixer, the amount of current produced from a transistor pair to which the signal cycle is being switched is also reduced thereby reducing noise from the transistor pair that is turning on for the next portion of a signal cycle.

Abstract: A surface mount, even harmonic mixer is preferably used in point-to-multipoint millimeter wave transceivers. The mixer includes an anti-parallel series arrangement of diodes in one or more ring quads to increase the input 1 dB compression point and third-order input intercept point (IP3), while maintaining the benefits inherent with even harmonic mixing.

Abstract: There is disclosed a radio frequency (RF) demodulation circuit comprising: 1) a first RF mixer having a first input port for receiving an in-phase RF signal having a frequency of RF and a second input port for receiving an in-phase local oscillator (LO) signal having a frequency of LO, wherein LO is approximately equal to one-half of RF, and wherein the first RF mixer generates a first intermediate frequency (IF) signal having a frequency of LO; 2) a second RF mixer having a first input port for receiving an out-of-phase RF signal having a frequency of RF and a second input port for receiving an out-of-phase local oscillator (LO) signal having a frequency of LO, and wherein the second RF mixer generates a second intermediate frequency (IF) signal having a frequency of LO; and 3) a first signal combiner for combining the first and second IF signals to generate a composite IF signal, wherein the first signal combiner combines a first leakage signal from the first RF mixer and a second leakage signal from the se

Abstract: An RF communications circuit having a reduced LO feed through image reject mixer is disclosed. The image reject mixer includes a quadrature phase transconductance stage coupled to a quadrature phase mixer of a quadrature phase mixer module and an in-phase mixer of an in-phase mixer module. The image reject mixer further includes an in-phase transconductance stage coupled to an in-phase mixer of the quadrature phase mixer module and a quadrature phase mixer of the in-phase mixer module. The output of the quadrature phase mixer and in-phase mixer of the quadrature phase mixer module are cross-coupled to form a quadrature phase local oscillator (LO) output and wherein the output of the quadrature phase mixer and in-phase mixer of the in-phase mixer module are cross-coupled to form an in-phase local oscillator (LO) output.

Abstract: A receiver circuit (12) includes a first gate (24) that receives an input signal (VIN0, VIN1) and has an output (32, 34) for providing an output signal (VG0, VG1). A shifting circuit (20) is coupled for shifting the common mode potential of the input signal to produce a shifted signal (VSH0, VSH1). A second gate (22) has an input (27, 28) that receives the shifted signal and an output coupled to the output of the first gate.

Abstract: A mixer circuit configured to operate in a bypass or mixing mode, and which comprises a mixer core, and a mode select circuit. The mixer core includes first and second switches, each of which has an input, and first and second outputs. The mode select circuit is coupled to the mixer core and includes third and fourth switches, which are collectively configured to operate in either a first state corresponding to the bypass mode, or a second state corresponding to the mixing mode. The input of the first switch is configured to receive a signal at a first frequency, wherein the first and second switches are configured to switch between their respective first and second outputs at a second frequency, and wherein, responsive to the state of the third and fourth switches, the first output of the first switch, and the second output of the second switch are each configured to output a signal which is either (i) at the first frequency, or (ii) a mixing product of the first and second frequencies.

Abstract: A single chip direct conversion transceiver that includes a substrate on which a mixer unit and a local oscillator are provided as a circuit, and a positive hole formed between the mixer unit and the local oscillator and filled with a conductive plug to block signal leakage. A shield ground surface is formed above the substrate and blocks signal leakage occurring when the signals received through the antenna are input into the mixer and signal leakage occurring when the reference signal is input into the mixer from the local oscillator. A first interconnection is formed above the shield ground surface and connects the mixer unit and the local oscillator. Dielectric layers are formed between the substrate and the shield ground surface and on the shield ground surface to cover the first interconnection.

Abstract: An RF modulator/switch selectably couples a locally generated and conducted RF signal or an antenna RF signal to a broadcast radio receiver. A local RF input receives the conducted RF signal. An antenna RF input receives the antenna RF signal in response to a radiated RF broadcast in a broadcast band. A resonant network has a first node coupled to the antenna RF input and has a resonant frequency corresponding to the broadcast band. A first relay has a first output selectably coupled to either the antenna RF input or a second node of the resonant network. A second relay has a second output selectably coupled to either the local RF input or the first output of the first relay. When the second relay selects the local RF input then the first relay selects the second node of the resonant network and when the second relay selects the first output of the first relay then the first relay selects the antenna RF input.

Abstract: A frequency agile sequential amplifier circuit that includes first and second RF amplifiers coupled by a SAW delay line, a double balanced mixer coupling the first RF amplifier to the SAW delay line, the output of the first RF amplifier providing a signal as a first input to the double balanced mixer and a variable pulse generator coupled to both said first and second RF amplifiers to cause them to sequentially and alternately conduct, and a divide/2 circuit coupling said variable pulse generator to said double balanced mixer as a second input at ½ the rate of said RF amplifiers to cause the sequential amplifier circuit to achieve frequency agility and to substantially maintain its sensitivity.

Abstract: A system and method is provided for generating a second LO signal to a second mixer of a plurality of receivers employed in a multimode communication device. A single PLO and VCO provides a high frequency second LO signal that is divided by divider components to provide a number of lower frequency second LO signals. The different high frequency second LO signal and the number of lower frequency second LO signals may be utilized for providing second LO signals for component employed in receiving communications from radio devices employing different communication standards and/or frequency ranges.

Abstract: It is an object of the present invention to provide an indoor mobile communication device having a simple structure, providing a sufficient communication range, and also providing for stable communication with a small fading effect.

Abstract: A power amplifier system has a high frequency power amplifier circuit section employing source-grounded enhancement type n-channel MESFETs for receiving a drain bias voltage and a gate bias voltage of zero volts or positive low potentials supplied from a unipolar power supply, and amplifying a superposed input signal therewith to output an amplified signal indicative of a change in drain currents. An output matching circuit section applies impedance matching to the amplified signal and outputs the resultant signal. A gate bias voltage circuit section supplies a gate bias voltage to the high frequency power amplifier circuit. When a forward direct current gate voltage is applied to a gate terminal with a source terminal coupled to ground, the DC gate voltage becomes greater than or equal to 0.65 volts, the DC gate voltage causing a gate current value per gate width of 100 micrometers to exceed 100 microamperes.