Abstract: A transmit in-phase quadrature (IQ) amplifier includes a common gain stage to receive an input signal and to generate an amplified signal. The amplifier includes an IQ poly-phase filter coupled to the common gain stage to receive the amplified signal from the common gain stage and outputs a four-phase signal. The amplifier includes an in-phase (I) phase switching gain stage coupled to the IQ poly-phase filter to receive I components of the four-phase signal and outputs an amplified phase switching I signal. The amplifier includes a quadrature (Q) phase switching gain stage coupled to the IQ poly-phase filter to receive Q components of the four-phase signal and outputs an amplified phase switching Q signal.

Abstract: The present invention discloses a power amplification apparatus having a digital pre-distortion mechanism that includes a digital pre-distortion circuit and a power amplifier. The digital pre-distortion circuit receives an original digital signal having an original real part and an original imaginary part. When a first one and a second one of the original real part and the original imaginary part are a low state voltage level and a high state voltage level, the digital pre-distortion circuit outputs a first and a second voltage levels equivalent to the low state voltage level as a first pre-distortion part and directly outputs the second one of the original real part and the original imaginary part as a second pre-distortion part to generate an input signal having an input real part and an input imaginary part each corresponding to one of the first pre-distortion part and the second pre-distortion part. The power amplifier receives the input signal to perform power amplification to generate an output signal.

Abstract: A system and method of the disclosure relates to satellite tracking. The system may comprise a tracking receiver that includes a first analog-to-digital (A/D) converter coupled between a sum input and a digital signal processor (DSP), a second A/D converter coupled between a difference input and the DSP, and a calibration output coupled to the sum input and coupled to the difference input. The first A/D converter may convert an signal received at the sum input into a sum digital signal, and provide the sum digital signal to the DSP. The second A/D converter may convert an signal received at the difference input into a difference digital signal, and provide the difference digital signal to the DSP. The tracking receiver may generate an calibration signal and provide the calibration signal through the calibration output.

Abstract: Tuning an antenna circuit of an actively transmitting tag to a frequency of an interrogator carrier signal after the tag was inserted into a host device is accomplished by detecting presence of the interrogator carrier signal at a location of the actively transmitting tag and hereafter setting capacitances of capacitors and/or inductances of coils comprised in said antenna circuit in a way that resonance of said antenna circuit is established while the antenna circuit is excited by a magnetic field of said interrogator carrier signal. This allows automatic tuning of an antenna circuit of an actively transmitting tag after it was inserted together with a miniature card into a host device, such as a mobile telephone, personal digital assistant, tablet PC and similar devices.

Abstract: Methods and systems for improving adjacent channel rejection performance in a wireless signal by a radio device in a mobile network. In one embodiment, a mobile radio network includes a first radio device (e.g., a subscriber), a second radio device, and a fixed radio apparatus (e.g., a base station or repeater). The first radio device receives a first channel signal having a first frequency offset with respect to a reference frequency. The first channel signal is associated with the second radio device. The first radio device measures the first frequency offset, determines a second frequency offset for a second channel signal, and transmits the second channel signal with the second frequency offset.

Abstract: An apparatus and a method. The apparatus includes a first low pass filter (LPF), a second LPF, a first analog-to-digital converter (ADC), a second ADC, a first discrete Fourier transform (DFT) unit, a second DFT unit, a second order intermodulation (IM2) tone amplitude measurement unit, and a calibration logic unit configured to simultaneously determine an in-phase mixer (I-mixer) digital-to-analog (DAC) code and a quadrature-phase mixer (Q-mixer) DAC code.

Abstract: An input receives a generated frequency having a first frequency component and a second frequency component. A filter block includes filter coefficients describing a relationship between the second frequency component and an environmental characteristic. The filter block predicts the first frequency component based on the environmental characteristic, and updates the filter coefficients based on an offset between the predicted first frequency component and a received frequency corresponding to the first frequency component.

Abstract: An electronically tunable equalizer is provided to a downlink (DL) and/or uplink (UL) signal processing path of a wireless communication unit incorporating a RF filter. The electronically tunable equalizer is pre-configured with a plurality of capacitance states, each representing a specific capacitance. The equalizer produces a different equalizer response for each of the plurality of capacitance states based on a received pass-band frequency signal. The plurality of equalizer responses is provided to the RF filter on a signaling processing path, thus affecting the RF filter's pass-band ripple. The RF filter's pass-band ripple is measured for each of the plurality of equalizer responses to determine a desired pass-band ripple. By configuring the electronically tunable equalizer to the capacitance state that produced the desired pass-band ripple, a ceramic RF filter may be used in the wireless communication unit for the benefit of lower cost and size, with reduced pass-band ripple.

Abstract: Methods and apparatuses to determine a frequency adjustment in a mobile wireless device are disclosed. A method includes determining a coarse frequency error estimate and multiple fine frequency error estimates; selecting at least one candidate fine frequency error estimate having a frequency value closest to a corresponding frequency value for the coarse frequency error estimate; and determining a frequency adjustment based on a combination of the coarse frequency error estimate and the selected at least one candidate fine frequency error estimate. In an embodiment, the method further includes calculating a confidence metric for the coarse frequency error estimate; when the confidence metric exceeds a threshold value, determining the frequency adjustment based on the candidate fine frequency error estimate; otherwise, determining the frequency adjustment based on a fine frequency error estimate in the plurality of fine frequency error estimates closest to a most recent previous fine frequency error estimate.

Abstract: A system is provided. The system includes an electrosurgical generator configured to measure, collect and record data pertaining to a characteristic of tissue as the tissue is being electrosurgically treated. A tuner configured to couple to the electrosurgical generator includes a tuning circuit providing a load having a variable complex impedance for the electrosurgical generator when the electrosurgical generator is connected thereto. A controller including stored data pertaining to impedance values is in operable communication with the electrosurgical generator for retrieving the recorded data pertaining to the characteristic of tissue. The controller is in operable communication with the tuner for varying a complex impedance of the load. The controller configured to compare the recorded data pertaining to the at least one characteristic of tissue with the stored data pertaining to the plurality of impedance values and to adjust the tuner to one of the plurality of impedance values.

Abstract: One embodiment relates to an apparatus for generating a data output signal. The apparatus includes a pre-emphasis filter and an edge-shape filter. The edge-shape filter includes a non-linearity correction stage that applies a non-linearity correction and a linear filter that applies linear filtering. Another embodiment relates to a method of generating tap coefficients for a pre-emphasis filter. A summation of products of tap coefficients and time-shifted base single-bit response waveforms is used to form a first waveform, and a measured single-bit response waveform is used to provide a second waveform. The tap coefficients are adjusted to fit the first waveform to the second waveform. Other embodiments, aspects, and features are also disclosed.

Abstract: A radio frequency (RF) communications system, which includes an RF power amplifier (PA) and an envelope tracking power supply, is disclosed. The RF communications system processes RF signals associated with at least a first RF communications band, which has a first bandwidth. The RF PA receives and amplifies an RF input signal to provide an RF transmit signal using an envelope power supply signal. The envelope tracking power supply provides the envelope power supply signal, which has switching ripple based on a programmable switching frequency. The programmable switching frequency is selected to be greater that the first bandwidth.

Abstract: Techniques for providing a transceiver with a sliding intermediate frequency (IF). In an aspect, a PLL generates a single local oscillator (LO) signal used for both up-conversion by a transmit (TX) signal path and down-conversion by a receive (RX) signal path, wherein the LO frequency is chosen as the TX carrier frequency. As the TX and RX carrier frequencies may generally differ by a variable amount, the RX signal path utilizing the (TX) LO frequency for down-conversion may be characterized as having a “sliding” IF. To accommodate the sliding IF receiver architecture, specific processing functions such as charge sampling, discrete-time analog band-pass filtering, and sub-sampling analog-to-digital conversion (ADC) are described.

Abstract: A method of and apparatus for detecting signal features including amplitude, phase and timing of recognizable input signals in a frequency band or spectrum of interest. One or more super-regenerative oscillators are provided, each having a center frequency and each detecting signal features of recognizable input signals in the frequency band or spectrum of interest during multiple, successive time slots. The center frequency of each of the one or more super-regenerative oscillators is varied between time slots in a selected sequence, preferably according to a Segmentlet algorithm. The one or more super-regenerative oscillators extract the signal features of each the recognizable input signals in different time slots and/or in different super-regenerative oscillator and with a different time-slot associated center frequency associated with the one or more super-regenerative oscillators, thereby providing a time-frequency-amplitude map of the frequency band or spectrum of interest.

Abstract: Systems and methods are described for the implementation of a full band cable receiver by using a combination of tuners (e.g., ultra-low power Tuners) and Analog-to-Digital Converters (ADCs) to attain the goal of digitization with reduced power and/or cost. The full-band capture cable receiver can overcome the constraints of conventional cable receiver systems and deliver multiple channels, thereby allowing operators to provide consumers with an increased number of services.

Abstract: The present invention relates to automatic gain control methods and apparatus for controlling a signal level of a signal at a predetermined location in a signal path of a receiver chain. An automatic gain controller comprises a local signal modifier device for selecting based on an error signal and an oscillator signal from a plurality of alternative oscillator signals, and for providing the selected oscillator signal to a signal mixer located in the receiver chain upstream of said predetermined location for frequency translation of an input signal to said signal mixer.

Abstract: A frequency offset of a received signal comprising a number of subsequently received data symbols is estimated. A first estimate is determined from a calculated change in phase of the received signal between two received symbols having a first time distance between them. At least one further estimate is determined from a calculated change in phase of the received signal between two received symbols having a different time distance. A frequency periodicity is determined for each estimate from the distance between the two received symbols from which the estimate was determined. A set of integer values is determined for each estimate so that frequency values calculated for each estimate as the frequency periodicity multiplied by the integer value added to the estimate are at least approximately equal to each other, and a corrected estimate of the frequency offset is determined from the integer values.

Abstract: In accordance with an example embodiment of the present invention, an apparatus comprises a first multiplier configured to convert a first frequency signal into a second frequency signal based at least in part on a first complex-valued local oscillator signal, a pair of low-pass filters configured to filter the second frequency signal, and a second multiplier configured to convert the filtered second frequency signal into a third frequency signal based at least in part on a second complex-valued local oscillator signal wherein the first frequency signal and the third frequency signal share the same frequency position and the pair of low-pass filters is configured based on an indication of allocated transmitted channels.

Abstract: A test system (200) for testing for missing or shorted parts within a tuner circuit includes a signal generator (202) for applying a harmonic-containing baseband time varying RF test signal to the tuner circuit. The tuner circuit is tuned to a harmonic of test signal. A detector 208 coupled to the baseband IF output of the tuner circuit detects the voltage generated in response to the applied RF test signal. A voltage measurement device (210) measures voltage detected by detector to provide an indication of the gain. Significant changes in the gain indicate missing part(s) or short circuits.

Abstract: A wireless communication unit has two or more communication modes including one or more mobile phone mode, in which mobile phone mode the wireless communication unit is able to transmit or receive wireless signals via an antenna from and/or to a mobile phone network in accordance with a communication protocol. The unit includes a baseband module and a radiofrequency module. A radiofrequency interface of the baseband module is connected to the radiofrequency module, for receiving and/or transmitting baseband signals from and/or to the radiofrequency module. The radiofrequency module includes a baseband interface, for receiving and/or transmitting the baseband signals to the baseband module and an antenna interface (AI) connectable to an antenna for receiving and/or transmitting radiofrequency signals from and/or to the antenna. A clock system is connected to the radiofrequency interface and the baseband interface.

Abstract: Embodiments provide a receiver and a method for receiving data transmitted via a combination of a first signal modulated at a first carrier frequency, and a second signal modulated at a second carrier frequency, different to the first carrier frequency. In one embodiment the receiver includes a local oscillator and is configured to adaptively configure the local oscillator to operate at a first local oscillator frequency and a second local oscillator frequency, different to the first frequency, in dependence on a signal strength of the first signal relative to a signal strength of the second signal.

Abstract: A modulation circuit for use in a radiofrequency transmitter includes a local oscillator circuit configured to generate one or more local oscillator signals at a desired frequency and with a duty cycle at or about twenty-five percent, and a modulator configured to generate one or more modulated signals responsive to the one or more local oscillator signals and one or more baseband information signals. In at least one embodiment, the modulation circuit includes a modulator comprising a combined mixing and transconductance circuit that includes a transistor circuit for each baseband information signal serving as a modulation input to the modulator. Each transistor circuit comprises a first transistor driven by the baseband information signal and coupling a modulator output node to a corresponding transconductance element, and a second transistor driven by one of the one or more local oscillator signals and coupling the corresponding transconductance element to a signal ground node.

Abstract: In one embodiment, the present invention includes a method for receiving a radio frequency (RF) signal and mixing the RF signal with a master clock to obtain a mixed signal, cyclically rotating the mixed signal to each of N gain stages for at least one cycle of the master clock, and summing the outputs of the N gain stages to provide an output signal.

Abstract: A radio-frequency (RF) apparatus, which may reside in a receiver or transceiver, includes receive-path circuitry. The receive-path circuitry includes a poly-phase filter and a harmonic filter. The poly-phase filter accepts an input signal and generates two output signals. One output signal of the poly-phase filter constitutes an in-phase (I) signal. The other output signal of the poly-phase filter constitutes a quadrature (Q) signal. The a harmonic filter couples to the poly-phase filter. The harmonic filter accepts as input signals the in-phase and quadrature output signals of the poly-phase filter.

Abstract: A first programmable frequency oscillator, which includes a first ramp comparator and programmable signal generation circuitry is disclosed. The programmable signal generation circuitry provides a ramping signal, which has a first frequency, based on a desired first frequency. The first ramp comparator receives the ramping signal and provides a first ramp comparator output signal based on the ramping signal. The first ramp comparator output signal is fed back to the programmable signal generation circuitry, such that the ramping signal is based on the desired first frequency and the first ramp comparator output signal. However, the first ramp comparator has a first propagation delay, which introduces a frequency error into the programmable frequency oscillator. Therefore, the first frequency is not proportional to one or more slopes of the ramping signal. As a result, the programmable signal generation circuitry compensates for the frequency error based on the desired first frequency.

Abstract: Systems and devices for controlling frequency drift in satellite broadcast systems. A receiver antenna system for a direct broadcast satellite signal communications system in accordance with one or more embodiments of the present invention comprises an oscillator, a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency, an analog-to-digital (A/D) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-real-time to a digital data stream, a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream, and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.

Abstract: A method and device for managing a reference oscillator within a wireless device is presented. The method includes selecting reference oscillator parameters associated with the lowest reference oscillator error, where the selection is based upon reference oscillator parameters derived using different technologies within a wireless device, acquiring a satellite based upon the selected reference parameters, determining the quality of the satellite-based position fix, and updating the reference oscillator parameters based upon the quality of the satellite-based position fix.

Abstract: A method for wireless communication includes adding a received DVB-H signal with a reference oscillator signal to generate an added DVB-H signal. The reference oscillator signal may be added at an input of a matching load. The matching load may be used to tune a wireless antenna that receives the received DVB-H signal based on a received signal strength indicator (RSSI) associated with the added DVB-H signal. The reference oscillator signal may be generated, and the generated reference oscillator signal may be amplified. The added DVB-H signal may be amplified subsequent to the adding. The RSSI associated with the added DVB-H signal may be determined. The tuning may occur during receiving of a preamble of a packet for the received DVB-H signal.

Abstract: A radio wave receiving apparatus is provided with a tuning circuit for bringing a receiving frequency of an antenna tuned in to a frequency of a desired wave, a frequency converting circuit for mixing a local oscillation signal with the signal received through the antenna, thereby converting the received signal into an intermediate frequency signal, a feed back loop including at least a portion of the tuning circuit for feeding back the received signal, a controller for detecting a level of the intermediate frequency signal to change a frequency characteristic of the tuning circuit, thereby obtaining a tuning point corresponding to the desired wave, wherein, the controller brings the feed back loop in operation, thereby changing the frequency characteristic of the tuning circuit, and when two peaks of a level of the received signal are detected while the frequency characteristic of the tuning circuit is changed, the controller selects as a tuning point corresponding to the desired wave a tuning point at which

Abstract: Apparatus and methods of manufacture for a wideband RF mixer are provided. The RF mixer includes an input, an LO input, and an output. A variable impedance tuner is disposed in an input signal path between the input port and the RF mixer, and a variable impedance tuner is disposed in an output signal path between the output and the RF mixer. The impedances of the variable impedance tuners are controllable for a particular frequency of operation with one or more digital or analog control signals.

Abstract: In one implementation, a receiver may have an analog front end with an amplifier to receive a radio frequency (RF) signal and a mixer to downconvert the signal to a baseband signal. Then, a demodulator may receive the baseband signal and obtain an audio signal therefrom. Still further, a controller may be coupled to receive a control signal corresponding to a variable impedance level, and control a local oscillator coupled to the mixer responsive to the control signal. The variable impedance may be controlled by a user to tune to the channel.

Abstract: The invention discloses a dual frequency multiplexer by which a first and second coaxial harmonic oscillator type band pass filters are disposed in a box. The box includes a base body, a cover plate and a cover body. The two coaxial harmonic oscillator type hand pass filters are located on the base body and spaced each other by a metal plate; the multiplexer port, first and second ports are positioned on lateral side of the base body. The blocking capacitors are contained in the coaxial chamber of the two coaxial harmonic oscillator type band pass filters. The cover plate is secured on the base body; the first and second direct current circuits are placed on the cover plate; the low pass filters of the first and second direct current circuits are fixed on an edge of a top surface of the coaxial chamber by means of a support member; the cover body and the base body are fastened with each other. The blocking capacitors each are of distributed parameter capacitor.

Abstract: An oscillator circuit having a source of an oscillating signal, a tank circuit including an inductor and a capacitor, and a discretely switchable capacitance module configured to control an amount of capacitance in the oscillator circuit. The discretely switchable capacitance module includes, in one embodiment, a capacitor coupled between a first node and a second node, a switch, having a control node, coupled between the second node and a third node; and a DC feed circuit, having a first end coupled to the second node and a second end configured to receive a first or second control signal. The control node of the switch is tied to a predetermined bias voltage. When the first control signal is applied, the capacitor is coupled between the first node and the third node via the switch such that the capacitor is coupled in parallel with the capacitor of the tank circuit, and when the second control signal is applied the capacitor is decoupled from the tank circuit.

Abstract: A rapidly adjustable local oscillation (LO) module for use in a radio transmitter or a radio receiver includes an oscillation generating module and a high frequency switching module. The oscillation generating module is operably coupled to generate a plurality of local oscillations. The high frequency switching module is operably coupled to, for a first one of a plurality of transmission paths, provide one of the plurality of local oscillations when a first transmission path selection indication is in a first state and provide another one of the plurality of local oscillations when the first transmission path selection indication is in a second state and, for a second one of the plurality of transmission paths, provide the one of the plurality of local oscillations when a second transmission path selection indication is in a first state and provide the another one of the plurality of local oscillations when the second transmission path selection indication is in a second state.

Abstract: A communication apparatus includes: a communication unit COM that performs operation control of a function involving transmission or reception of an electromagnetic wave by an antenna; a touch sensor module TSM having an oscillation circuit and an electrode connected to the oscillation circuit; a power supply PS that supplies power to the oscillation circuit; and a power supply controller PSCON that controls supply of power by the power supply PS. The touch sensor module TSM detects a contact operation based on an oscillation state of the oscillation circuit which varies in accordance with a contact operation. As a result, a state where the power supply PS is supplying power to the oscillation circuit under the control of the power supply controller PSCON and a state where the communication unit COM is performing operation control of the function involving transmission or reception of an electromagnetic wave do not exist concurrently.

Abstract: A radio-frequency receiver. The radio-frequency receiver includes a first and second low noise amplifier (LNA), a local oscillating module, and a first, second, and third mixer. The first LNA amplifies a first RF signal. The local oscillating module generates a first, second and third local oscillating signals. The first local oscillating signal is generated according to the second local oscillating signal. The first mixer mixes the first RF signal with the first local oscillating signal to generate an intermediate frequency signal. The second LNA amplifies a second RF signal. The second and third mixers can be operated in two modes. The second and third mixers mix the intermediate frequency signal to generate a first and second baseband signal respectively in the first mode, and the second and third mixers mix the second RF signal with the second and third oscillating frequency respectively in a second mode.

Abstract: A modulation circuit for use in a radiofrequency transmitter includes a local oscillator circuit configured to generate one or more local oscillator signals at a desired frequency and with a duty cycle at or about twenty-five percent, and a modulator configured to generate one or more modulated signals responsive to the one or more local oscillator signals and one or more baseband information signals. In at least one embodiment, the modulation circuit includes a modulator comprising a combined mixing and transconductance circuit that includes a transistor circuit for each baseband information signal serving as a modulation input to the modulator. Each transistor circuit comprises a first transistor driven by the baseband information signal and coupling a modulator output node to a corresponding transconductance element, and a second transistor driven by one of the one or more local oscillator signals and coupling the corresponding transconductance element to a signal ground node.

Abstract: Selectable sizes for a local oscillator (LO) buffer and mixer are disclosed. In an embodiment, LO buffer and/or mixer size may be increased when a receiver operates in a high gain mode, while LO buffer and/or mixer size may be decreased when the receiver operates in a low gain mode. In an embodiment, LO buffer and mixer sizes are increased and decreased in lock step. Circuit topologies and control schemes for specific embodiments of LO buffers and mixers having adjustable size are disclosed.

Abstract: A system and method provide adaptive filtering of radio frequency (RF) signals. Multiple signals are received in a predetermined RF spectrum, the signals including a desired signal and multiple potentially interfering signals. A first signal of the potentially interfering signals is down-converted to a baseband signal, and a power of the baseband signal is determined. When the power exceeds a predetermined threshold power, a first notch filter, corresponding to a frequency of the first signal, is activated.

Abstract: A frequency synthesizer comprises a tunable oscillator (23) which provides an output signal of the frequency synthesizer, and a sampling phase detector (6) which receives the output signal from oscillator (23) and a reference signal and provides a phase difference signal representative of a phase difference between the output signal and the reference signal, which controls the frequency of the oscillator (23). The frequency of the oscillator (23) is further controlled by a frequency difference signal from a frequency detector (3), which is representative of a frequency difference between the output signal and the reference signal.

Abstract: A communication device and method of removing an LO leakage signal from a signal path on the fly is disclosed. The signal path may be that of a transmitter or receiver. An initial RF output signal, containing a desired RF output signal and an LO leakage signal, is supplied from a feedforward path to a combiner/splitter on a feedback path. A 180° out-of-phase copy of the desired RF output signal is also supplied to the combiner/splitter. The resulting LO leakage signal is down-converted and the power of the down-converted signal determined and used to suppress the LO leakage signal. The resulting LO leakage signal is also supplied to the feedforward path of the feedback loop.

Abstract: A processing device (40) for processing an analog complex input signal generated by downconversion of an aggregated-spectrum radio-frequency signal in a radio-receiver (10), wherein the complex input signal comprises a plurality of sub bands (S1-S4) scattered across a total frequency band (4) of the complex input signal. The processing device (40) comprises a plurality of processing paths (P1-PN). wherein each processing path (P1-PN) is adapted to process an associated sub band (S1-S4). Each processing path comprises a complex mixer (CM1-CMN) adapted to frequency translate the complex input signal, and an analog channel-selection filter (CSF1-CSFN) arranged to filter an output signal of the complex mixer (CM1-CMN) and pass the frequency translated associated sub band (S1-S4). A control unit (60) is adapted to receive control data indicating frequency locations of the sub bands (S1-S4) and, for each processing path (P1-PN).

Abstract: A frequency synthesizer includes: a frequency source generating a reference signal that includes a plurality of pulses having periodicity based on a reference frequency; a feedback loop that includes, a phase detector circuit, a loop filter, a controlled oscillator that generates an output signal at an output, and a loop divide circuit; a non-linear circuit element at an input of the phase detector circuit, which generates intermodulation distortion that causes at least one spurious signal at the output; and a controller controlling the loop divide circuit and the non-linear circuit element. The frequency synthesizer further includes a dither circuit that adjusts the timing of some of the pulses of the reference signal based on a parameter provided by the controller to the non-linear circuit element, thereby, providing a jittered reference signal to the non-linear circuit element for attenuating the at least one spurious signal at the output.

Abstract: A system for utilizing circular polarized signals to perform satellite communication to mobile users. The satellite includes transponders, each transponder providing linearly polarized signals and at least two orthogonal linear polarized transponders. A plurality of mobile users with a circularly polarized antenna for receiving signals from the satellite, and singly circular or linear polarized transmit antennas for transmitting signals to the satellite. Circuits for providing a correction scheme implemented in a hub side to offset frequency error between two channels produced by the satellite transponder local oscillators mismatch.

Abstract: A dual conversion receiver architecture that converts a radio frequency signal to produce a programmable intermediate frequency whose channel bandwidth and frequency can be changed using variable low-pass filtering to accommodate multiple standards for television and other wireless standards. The dual conversion receiver uses a two stage frequency translation and continual DC offset removal. The dual conversion receiver can be completely implemented on an integrated circuit with no external adjustments.

Abstract: A modulation circuit for use in a radiofrequency transmitter includes a local oscillator circuit configured to generate one or more local oscillator signals at a desired frequency and with a duty cycle at or about twenty-five percent, and a modulator configured to generate one or more modulated signals responsive to the one or more local oscillator signals and one or more baseband information signals. In at least one embodiment, the modulation circuit includes a modulator comprising a combined mixing and transconductance circuit that includes a transistor circuit for each baseband information signal serving as a modulation input to the modulator. Each transistor circuit comprises a first transistor driven by the baseband information signal and coupling a modulator output node to a corresponding transconductance element, and a second transistor driven by one of the one or more local oscillator signals and coupling the corresponding transconductance element to a signal ground node.

Abstract: Systems of clock generation for integrated radio frequency receiver. In an integrated radio frequency receiver, a mixer is often used to down convert the incoming radio frequency signal. The down converted signal is then digitized and digital signal processing circuitry is used for efficient and flexible implementation of various functions to receive the underlying audio and/or data information. The mixer requires clock generation circuitry to provide a proper local oscillator signal for a selected channel. On the other hand, the digital signal processing circuitry requires its separate digital clock for proper operations. The clock generation system utilizes single local oscillator generation circuitry to provide the local oscillator signals required by the mixer and the digital clock signals required by the digital signal processing circuitry.

Abstract: According to an example embodiment, an apparatus is provided in a wireless transceiver. The apparatus may include a circuit configured to generate a first frequency signal (e.g., a VCO signal). A local oscillator (LO) generator may be provided that includes a frequency divider to divide the first frequency signal, and an image rejection mixer configured to mix the first frequency signal with an output of the frequency divider to generate an LO signal. In this manner, the LO generator may generate a desired LO signal while substantially rejecting or suppressing an unwanted sideband or image signal, according to an example embodiment.

Abstract: Certain aspects of a method and system for tuning an antenna using injection may include mixing a received DVB-H signal with a reference oscillator signal to generate an added DVB-H signal. A mixed signal may be generated from the added DVB-H signal using the reference oscillator signal. A wireless antenna that receives the received DVB-H signal may be tuned based on a received signal strength indicator (RSSI) associated with the mixed signal. The reference oscillator signal may be generated and then may be amplified. The first mixed DVB-H signal may be amplified prior to the generating of the mixed signal. The RSSI associated with the mixed signal may be determined. The tuning may occur during receiving of a preamble of a packet for the received DVB-H signal and/or during receiving of a plurality of packets for the received DVB-H signal.

Abstract: A technique of frequency hopping communication capable of high-speed switching of a plurality of signals having ultra-wide band 528 MHz bandwidth at high-speed and setting and switching a band center frequency and the number of bands arbitrary is provided. A radio transceiver has a frequency hopping communication function of UWB system for switching the ultra wide band signal. In the device, high-speed frequency hopping is realized by controlling an SSB mixer in a local oscillator circuit and switching the frequency of a DDS. The device sets NCO data to the DDS and switches a quadrature phase signal of an output, and switches a signal input of an input terminal of the SSB mixer by a control of a phase switching switch. One of a sum component and a difference component of a mixture of first and second quadrature phase signals is outputted from the output terminal of the SSB mixer.