Abstract: Broadband feedforward power amplifiers are disclosed herein. In certain embodiments, a broadband feedforward power amplifier includes a power amplifier electrically connected between a radio frequency (RF) input and an RF output, and a feedforward compensation circuit including a first amplifier electrically connected in parallel with the power amplifier, a load impedance, and a second amplifier electrically connected between the radio frequency input and the load impedance. The feedforward compensation circuit generates a compensation signal based on sensing an output of the first amplifier and an output of the second amplifier, and provides the compensation signal to the radio frequency output to thereby compensate the power amplifier for non-linearity.

Abstract: Thermal structures and, more particularly, improved thermal structures for heat transfer devices and spatial power-combining devices are disclosed. A spatial power-combining device may include a plurality of amplifier assemblies and each amplifier assembly includes a body structure that supports an input antenna structure, an amplifier, and an output antenna structure. One or more heat sinks may be partially or completely embedded within a body structure of such amplifier assemblies to provide effective heat dissipation paths away from amplifiers. Heat sinks may include single-phase or two-phase materials and may include pre-fabricated complex thermal structures. Embedded heat sinks may be provided by progressively forming unitary body structures around heat sinks by additive manufacturing techniques.

Abstract: Various embodiments disclosed herein provide for a low complexity transmitter structure for active antenna arrays by reducing the number of digital predistortion extraction loops that need to be performed. Digital predistortion (DPD) corrects any non-linearities in a power amplifier. By determining which power amplifiers have similar characteristics in an array, and thus may use similar predistortion coefficients, once the DPD coefficients are determine for one of the grouped power amplifiers, DPD can be performed on each of the grouped power amplifiers based on the DPD coefficients.

Abstract: A consecutive Doherty amplifier is disclosed. The Doherty amplifier includes a carrier amplifier, a power splitter, a peak amplifier, and a phase compensator. The carrier amplifier receives a radio frequency signal with interposing any signal splitters. The power splitter splits an output of the carrier amplifier into first and second split signals. The phase compensator transfers the second split signal to the peak amplifier. The first split signal is combined with the output of the peak amplifier.

Abstract: A method for calibrating a phase nonlinearity of a digital-to-time converter is provided. The method includes generating, based on a control word, a reference signal using a phase-locked loop. A frequency of the reference signal is equal to a frequency of an output signal of the digital-to-time converter. Further, the method includes measuring a temporal order of a transition of the output signal from a first signal level to a second signal level, and a transition of the reference signal from the first signal level to the second signal level. The method additionally includes adjusting a first entry of a look-up table based on the measured temporal order.

Abstract: A radio frequency (RF) system is described for use in a wireless communication device. The RF system may contain power amplifiers, additional circuitry and components (e.g., gain controllers, phase shifters), and/or antennas. The RF system is described in a variety of different configurations with its functionality divided up over several single chip circuits. Using the single chip circuits simplifies assembly, reduces size, and allows for high speed RF performance demanded by fixed and mobile wireless standards. The system may use a first amplifier circuit combined with an adjacent channel leakage correction circuit so that the output of the first amplifier has the signal leakage substantially cancelled.

Abstract: An amplifying device includes: an amplifying circuit connected between an input terminal and an output terminal and amplifying a signal input in an amplification mode; and a bypass circuit including a filter connected to a bypass path for bypassing the amplifying circuit, wherein the bypass path is in an off-state in the amplification mode and is in an on-state in a bypass mode, and the filter bypasses an input high-frequency signal to ground, in the amplification mode.

Abstract: The disclosed technology is related to a radio-frequency (RF) amplifier having a bypass circuit and a resonant structure to improve performance in a bypass mode (e.g., a low gain mode). The disclosed amplifiers have a resonant structure that effectively isolates an amplifier core from a bypass circuit. For example, in a bypass mode, the resonant structure is configured to create an open impedance looking into the amplifier core input. This effectively removes any loading from the amplifier core to the bypass circuit. The disclosed amplifiers with resonant structures improve linearity performance in bypass modes due at least in part to the open impedance to the amplifier core provided by the resonant structure.

Abstract: Certain aspects of the present disclosure provide apparatus and techniques for digital-to-analog conversion. One example apparatus generally includes a first digital-to-analog converter (DAC) having an input coupled to a digital input node of the apparatus, a second DAC, a digital processor coupled between the digital input node and an input of the second DAC, and a combiner coupled to the first DAC and the second DAC.

Abstract: A method and base station transmitter for providing offline tuning of a base station transmitter. The base station transmitter includes a feed-forward power amplifier comprising a Radio Frequency (RF) input and an RF output. The base station transmitter also includes a simulated carrier generator operatively coupled to the feed-forward power amplifier prior to the carrier cancellation loop. The simulated carrier generator provides a simulated carrier signal including one or more individual carrier frequencies to the RF input. The base station transmitter also includes a processor that is operatively coupled to the feed-forward power amplifier and the simulated carrier generator. The processor performs tuning of a carrier cancellation loop using the simulated carrier signal when the processor determines that a carrier signal is not present.

Abstract: The disclosed technology is related to a radio-frequency (RF) amplifier having a bypass circuit and a resonant structure to improve performance in a bypass mode (e.g., a low gain mode). The disclosed amplifiers have a resonant structure that effectively isolates an amplifier core from a bypass circuit. For example, in a bypass mode, the resonant structure is configured to create an open impedance looking into the amplifier core input. This effectively removes any loading from the amplifier core to the bypass circuit. The disclosed amplifiers with resonant structures improve linearity performance in bypass modes due at least in part to the open impedance to the amplifier core provided by the resonant structure.

Abstract: Circuitry, which includes a PA power supply and RF PA circuitry, is disclosed. The RF PA circuitry includes a group of RF PAs and a group of PA decoupling circuits. The group of RF PAs includes a first RF PA and a second RF PA. The group of PA decoupling circuits includes a first PA decoupling circuit and a second PA decoupling circuit. The PA power supply provides a first PA power supply output signal to at least one of the group of RF PAs and to at least one of the group of PA decoupling circuits. The first PA decoupling circuit is coupled across the first RF PA, is programmable, and at least partially decouples the first RF PA from other circuitry. The second PA decoupling circuit is coupled across the second RF PA and at least partially decouples the second RF PA from other circuitry.

Abstract: The present disclosure discloses an LLC resonant converter and a method for suppressing ripples in output voltage of the LLC resonant converter. The LLC resonant converter comprises: a half-bridge or full-bridge chopper having a driving circuit, an inductance-capacitance series resonant network coupled to the chopper, an isolation transformer coupled to the resonant network, and a rectification and filtering circuit coupled to the isolation transformer; a feedforward controller coupled to generate a feedforward signal based on an input voltage; and a controlled oscillator coupled to receive the feedforward signal from the feedforward controller and to control an operating frequency of the chopper via the driving circuit based on the feedforward signal. Thus, a feedforward correction is provided for the LLC resonant converter, so that ripples in a DC output voltage of the LLC resonant converter are reduced.

Abstract: Apparatus and methods for low noise amplifiers (LNAs) are provided herein. In certain configurations, an LNA includes a gain stage and a bypass stage electrically connected in parallel with one another between an input and an output. The bypass stage and the gain stage are selectively activated based on a mode of the LNA. For example, the gain stage provides inverting amplification to an input signal received at the input in a gain mode. Additionally, the bypass stage provides a low gain path from the input to the output in a bypass mode. Additionally, the bypass stage includes a balun that provides inversion to the bypass stage such that a phase delay through the bypass stage is similar to a phase delay of the gain stage.

Abstract: An amplification circuit includes a first amplifier circuit and a second-stage amplifier. The second-stage amplifier is connected to the amplifier to form a multi-stage amplification circuit. The first amplifier circuit includes a first-stage amplifier and a bypass circuit. The bypass circuit includes a first transistor. A first end of the first transistor is coupled to the input end of the first amplifier circuit, a second end of the first transistor is coupled to the output end of the first amplifier circuit, and a third end of the first transistor is coupled to a supply voltage. The first end of the first transistor is further coupled to a first control terminal to receive a control signal for controlling a bias voltage of the first transistor, so as to make the amplification circuit work in different operation modes.

Abstract: A power amplifier module includes a driver transistor having first, second, and third terminals, a radio-frequency input port coupled to the first terminal of the driver transistor, a cascode transistor having first, second, and third terminals, the second terminal of the cascode transistor being coupled to the third terminal of the driver transistor, a radio-frequency output port coupled to the second terminal of the cascode transistor, and a coupling path connecting the first terminal of the cascode transistor to the third terminal of the cascode transistor, the coupling path including a capacitor.

Abstract: A frequency band selection device that can be inserted into a signal transmission line of a CATV system on the premise of a user includes at least two signal path sets between a tap side and a premise side. Each signal path set includes two discrete signal paths, a high frequency signal path for a downstream bandwidth and a low frequency signal path for an upstream bandwidth. The high frequency signal path and the low frequency signal path are separated by a cut-off transition frequency that is different for each signal path set. The device further includes a switch controller having at least two discrete switch positions. The switch controller chooses one of the switch positions as a result of an information signal. Each of the switch positions corresponds to a respective one of the signal path sets.

Abstract: An attenuator having an impedance that is controllable by a first setpoint signal is coupled to a transmission line. A matching circuit having an impedance that is controllable by a second setpoint signal is also coupled to the transmission line. A transformer circuit block also coupled to the transmission line has a complex impedance. A control circuit sets the first and second setpoint signals so as to control a conjugate impedance relationship between the variable impedances presented by the attenuator and matching circuit relative to the complex impedance of the transformer circuit.

Abstract: Described examples include Ethernet physical layer (PHY) interface integrated circuits with transmit interface circuitry for transmitting data to an Ethernet network through a magnetic interface, which includes a voltage mode first amplifier with an output that generates a first voltage signal from a supply voltage according to a data input signal. The transmit interface circuit also includes a feedforward second amplifier circuit with an output stage that operates in a first mode to generate a current signal from the supply voltage according to the first voltage signal and to provide the current signal to the first amplifier output to boost a peak voltage at the output above the supply voltage to facilitate support for higher peak signal voltage swings for 10Base-T applications while using 2.5 volt or other low voltage supply levels.

Abstract: A CMOS channel select filter for DVB-H direct-conversion receives based on a transresistance amplifier (TRA) is disclosed. The channel select filter includes a fully differential transresistance amplifier (FDTRA) configured to change an input current at each differential input terminal to a voltage at each differential output terminal based on an impedance at a corresponding differential impedance terminal. The channel select filter also includes two feedback resistors, each having one end connected to a respective differential output terminal of the FDTRA and having another end connected to the node, two first capacitors, each connected between ground and the node, and two second capacitors, each connected between ground and a respective differential impedance terminal.

Abstract: There is disclosed an envelope tracking modulated supply arranged to generate a modulated supply voltage in dependence on a reference signal, comprising a low frequency path for tracking low frequency variations in the reference signal and including a switched mode power supply, a correction path for tracking high frequency variations in the reference signal and including a linear amplifier, a feedback path from the output of the linear amplifier to the input of the linear amplifier, and a combiner for combining the output of the switched mode power supply and the output of the linear amplifier to generate a modulated supply voltage.

Abstract: Methods and systems for multi-path video and network channels may comprise a communication device comprising a wideband tuner (WB) and a narrowband tuner (NB). A video channel and a network channel may be received in the WB when the device is operating in a first stage. A video channel and a network channel may be received in the WB and the network channel may also be received in the NB when the device is operating in a second stage. The network channel may be received in the NB when the device is operating in a third stage. The reception of the network channel from both the WB and NB may enable a continuous reception of the network channel in a transition between the first and third stages. The WB may be operable to receive a plurality of channels and the NB may be operable to receive a single channel.

Abstract: Embodiments of the present invention provide a apparatus. The apparatus includes: N timing phase adjusters, a level calculator, and a first selector, where N is an integer greater than or equal to 2; the timing phase adjuster is configured to perform phase adjustment on a first signal according to a phase adjustment value, to obtain an adjusted first signal, where the first signal is a baseband signal, and the N timing phase adjusters respectively correspond to different phase adjustment values; the level calculator is configured to acquire level fluctuation values, within a preset time, of N adjusted first signals, determine an identifier of an adjusted first signal corresponding to a minimum level fluctuation value, and send the identifier to the first selector; and the first selector is configured to output the adjusted first signal corresponding to the identifier.

Abstract: A radio-frequency (RF) module includes a driver transistor having a base, collector and emitter, an RF input port coupled to the base of the driver transistor, a cascode transistor having a base, collector and emitter, the emitter of the cascode transistor being coupled to the collector of the driver transistor, an RF output port coupled to the collector of the cascode transistor, and a coupling path connecting the base of the cascode transistor to the emitter of the cascode transistor, the coupling path including a capacitor.

Abstract: A circuit and method for an audio op-amp that is configured to minimize crossover distortion between push and pull components of the audio op-amp. The audio op-amp includes an input stage that receives differential input signals and generates an output that amplifies the difference between the input signals. The audio op-amp further includes an output stage that receive the amplified signal and generate an audio output signal for playback by a speaker system. The output stage includes a diamond driver circuit that buffers the input stage from the speaker system, a boost circuit that includes a pair of boosting transistors that amplify the current of the amplified signal, and a biasing circuit that provides bias currents to the transistors of the boost circuit in a manner that minimizes crossover distortion between the boosting transistors.

Abstract: A low-frequency band suppression enhanced anti-reversal power system stabilizer is presented by the invention. Currently the widely used PSS2B power system stabilizer needs lead elements above Order 2 to meet the phase compensation requirement of DC blocking signal of active power, thus quickly increasing high-frequency band gain, restricting allowable total setting gain of PSS, limiting low-band gain and reducing low-frequency band suppression ability of power system stabilizer. The invention will add generator speed signal ? (which is treated by DC blocking element and corrected by parallel proportional differential PD) and active power signal Pe (which is treated by DC blocking element and gained by gain factor Ks3) to get equivalent synthetic mechanical power of power system stabilizer.

Abstract: A device, system and method for a wideband low noise amplifier is provided. The device may include a main amplifier and an error amplifier. In each amplifier is a phase inverter configured to invert the incoming signal. Additionally, rather than being formed from discrete components, the conductors of this wideband low noise amplifier are formed from microwave monolithic integrated circuits to provide for greater efficiency, which enables the low noise amplifier to operate in wideband rather than narrowband. A method of using the same is also provided.

Abstract: Systems and methods for determining the DC offset of a wireless device including the antenna are disclosed. Systems and methods for calibrating or cancelling the DC offset are also disclosed.

Abstract: A device and method for controlling reproduction of an audio signal is provided, wherein the device is operated by means of an energy storage device. The method comprises the steps of deactivating a normal mode and activating an energy saving mode. Power consumption from the energy storage device for reproduction of the audio signal is reduced in the energy saving mode when compared to the normal mode. The method comprises reducing in the energy saving mode, a bass frequency component of a frequency spectrum of the audio signal and outputting the audio signal with reduced bass frequency component. The method further comprises ascertaining a charge state of the energy storage device and controlling the reduction in the bass frequency component based on a decrease in the charge state of the energy storage device.

Abstract: The disclosure provides circuitry and methods to determine the reflection coefficient of a transmission line connected another physical element or device such as an antenna. The outgoing and the reflected signals on the transmission line are compared using two separate paths, with one path going through a signal conditioning circuitry such as an equalizer. The two paths are then combined and detected. A lookup table may be used for non-linear responses.

Abstract: A novel and useful linear, efficient, smart wideband CMOS hybrid power amplifier that combined an analog linear amplification path and a digital power amplification (DPA) path. PA path control logic analyzes the input I and Q signals and determines which amplification paths to steer the input I and Q signals to. The analog linear amplification path comprises digital to analog converters for both I and Q paths and one or more analog linear power amplifiers. The digital power amplification path comprises I and Q up-sampling circuits and I and Q RF DAC circuits (e.g., digital PA circuits). In operation, the PA path control logic compares the I and Q signals to thresholds (which may or may not be different) and based on the comparisons, selects one or more paths for the input I and Q signals. Whether the signals from the analog and digital amplification paths are to be combined or selected (i.e.

Abstract: Disclosed is a multi-port power amplifier (“MPA”) having an input hybrid matrix (“IHM”), an output hybrid matrix (“OHM”), and a plurality of high-power amplifier (“HPA”) chains. The MPA may include a plurality of adjustable delay modules (“ADMs”) in signal communication with the IHM and the plurality of HPA chains. Each adjustable delay module (“ADM”) of the plurality of ADMs may be in signal communication with the IHM and a corresponding HPA chain of the plurality of HPA chains.

Abstract: RFID systems are disclosed that include at least one RFID receiver system and a distributed exciter architecture. Exciters can be connected via wired and/or wireless connections to the RFID receiver system, which can control activation of the exciters to detect the presence of RFID tags within interrogation spaces defined by the exciter topology. One embodiment includes an RFID receiver system configured to detect information from RFID tags within a receive coverage area, and a plurality of exciters defining a plurality of interrogation spaces within the receive coverage area of the receiver system. The receiver system is configured to transmit a control signal that identifies one of the exciters and includes information indicative of an RFID tag interrogation signal, the exciters are configured to receive the control signal, and the exciter identified in the control signal is configured to illuminate an interrogation space with the RFID tag interrogation signal.

Abstract: A power amplifier (PA) has been disclosed for linearity improvement. The PA comprises at least an amplifying transistor and at least an auxiliary transistor. Each amplifying transistor of the at least an amplifying transistor includes a first terminal for receiving an input signal of the PA, a second terminal for delivering an output signal of the PA, and a third terminal. Each auxiliary transistor of the at least an auxiliary transistor includes a first terminal, a second terminal coupled to the second terminal of the at least an amplifying transistor, and a third terminal electrically connected to the first terminal of the at least an amplifying transistor.

Abstract: A low noise amplifier (LNA) has been disclosed for the noise and linearity performance improvement. The LNA includes an amplifying transistor and an auxiliary transistor. The amplifying transistor includes a first terminal for receiving an input signal of the LNA, a second terminal for outputting an output signal of the LNA, and a third terminal. The auxiliary transistor has a first terminal, a second terminal coupled to the second terminal of the amplifying transistor, and a third terminal electrically connected to the first terminal of the amplifying transistor.

Abstract: The present invention discloses a mobile communications terminal. The mobile communications terminal includes a signal processing module and a radio frequency power amplifier, where the signal processing module outputs, to a radio frequency signal input end of the radio frequency power amplifier, a radio frequency signal corresponding to one group of data packets, and synchronously outputs an enable signal to an enable signal input end of the radio frequency power amplifier; and the signal processing module periodically stops outputting the enable signal to the enable signal input end within first predetermined duration, and outputs, to the radio frequency signal input end, a radio frequency signal corresponding to at least one piece of pilot data and synchronously outputs the enable signal to the enable signal input end within second predetermined duration.

Abstract: Disclosed herein are an analog compensation circuit and a method for tuning an analog compensator in full-duplex transmission systems. An embodiment analog compensation circuit includes a secondary receiver configured to receive and convert a sampled self-interference signal to a baseband self-interference signal. A tuner is coupled to the secondary receiver and configured to receive a baseband transmit signal and the baseband self-interference signal, and to compute complex gains according to the baseband transmit signal and the baseband self-interference signal. An analog compensator is coupled to the tuner and has multiple branches. The analog compensator is configured to receive the complex gains and use them to adjust respective attenuators and phase shifters of the branches. The analog compensator is further configured to process a sample of a transmit signal using the branches, the transmit signal being up-converted from a new baseband transmit signal.

Abstract: A linear amplifier circuit includes a multi-stage power amplifier that can amplify an input signal to produce an output signal, and a gain feedback control circuit coupled with the output and the input of the multi-stage power amplifier. An adjacent-channel leakage feedback control circuit can detect the output signal at the output of the multi-stage power amplifier and reduce adjacent-channel leakage in the output signal over an output power range based on the detected output signal.

Abstract: An unbalanced linear power amplifier (PA) is disclosed having a quadrature coupler with a 90° phase input port, a 0° phase input port, an output termination port, and a signal output port. Each of the 90° phase input port, the 0° phase input port, the output termination port, and the signal output port have a characteristic resistance (Ro). Also included is a first PA having an output coupled to a 90° phase input port of the quadrature coupler and a second PA having an output coupled to a 0° phase input port of the quadrature coupler. Biasing circuitry provides the first PA and the second PA with a similar gain. A tuning network is coupled between the output termination port and ground. The tuning network has an isolation resistance in series with an isolation inductance, wherein the isolation resistance is between about 0.02*Ro ? and 0.8*Ro ?.

Abstract: A hybrid load pull tuner system uses a combination of a passive and active tuner system. A closed loop system means that the system is independent of the available power of the device under test (DUT). The proposed hybrid system is formed around a closed loop Gamma Boosting Unit (GBU) consisting of two back to back broadband directional couplers, broadband variable time-delay, broadband variable phase-shifter and a broadband microwave amplifier, all inserted in the coupled path of the couplers; the GBU is connected in cascade with a passive tuner and boosts its reflection factor; for this the amplifier must have enough linear power and gain to match the difference between the power reflected back to the DUT by the passive tuner and the desired total reflected power to reach the expected Gamma, considering coupling loss and insertion loss of the test fixture.

Abstract: A circuit for receiving data in an integrated circuit is described. The circuit comprises a receiver configured to receive an input signal and to generate output data based upon the input signal, the receiver having a level detection circuit coupled to receive the input signal; and a calibration circuit coupled to the receiver, the calibration circuit having an input for receiving the input signal; an error detection circuit coupled to the input, the error detection circuit coupled to receive the input signal, a first reference voltage and a second reference voltage; and a control circuit coupled to an output of the error detection circuit, wherein the control circuit selectively generates either an offset control signal or an amplitude control signal based upon comparisons of the input signal to the first reference voltage and the second reference voltage. A method of receiving data is also disclosed.

Abstract: An apparatus and method linearize a power amplifier in a transmitter by using a dual time alignment scheme. A first adjustable time delay unit delays a modulator signal input of a power amplifier. A first time delay estimator estimates a time delay between the delayed feedback signal and the reference signal, and adjusts the first adjustable time delay unit based on the estimated time delay between the delayed feedback signal and the reference signal. A second adjustable time delay unit delays the feedback signal. And a second time delay estimator estimates the time delay between the delayed feedback signal and the reference signal, and adjusts the second adjustable time delay unit based on the estimated time delay between the delayed feedback signal and the reference signal.

Abstract: An apparatus for active feed forward electromagnetic interference (EMI) filtering, including, a noise detection and current reconstruction circuit that receives EMI noise occurring at a noise source, and noise voltage compensation circuit operatively coupled to the noise detection and current reconstruction circuits. The active feed forward circuit generates a noise voltage compensation signal based on the EMI noise reconstructed by the noise detection circuit.

Abstract: According to one embodiment, there is provided a semiconductor device including a first amplifier and a second amplifier. The first amplifier has an input terminal to receive a first signal and an output terminal to output a second signal. The second amplifier is configured to receive the first signal and a correction data, to generate a correction signal according to the first signal and the correction data, and to output the generated correction signal to the output terminal of the first amplifier so as to add the first signal and the generated correction signal.

Abstract: Systems and methods for suppressing transmitter noise in a receive band of a co-located receiver that are suitable for wideband applications are disclosed. In one embodiment, an analog radio frequency transmit signal output by a transmitter includes a desired signal in a transmit band of the transmitter and transmitter noise in a receive band of a main receiver. A secondary receiver obtains a secondary receiver input signal that is representative of at least the transmitter noise in the receive band of the main receiver and outputs a digital feedforward signal. A digital feedforward transmit noise cancellation subsystem generates a digital transmitter noise cancellation signal that is representative of the transmitter noise in the receive band based on the digital feedforward signal and subtracts the digital transmitter noise cancellation signal from a digital receive signal output by the main receiver to thereby provide a compensated digital receive signal.

Abstract: A technique for a reconditioning equalizer filter for non-constant envelope signals is described. The input to a transmitter chain is modified by a reconditioning equalizer filter, prior to being applied to the transmitter. The reconditioning equalizer filter modifies and smoothens the amplitude of the signal. The modified and smoothened signal has its peaks reduced which results in lower Crest Factor. The input to the reconditioning equalizer filter could be a baseband, intermediate frequency (IF) or radio frequency (RF) signal. When the signal is an IF or RF signal, it needs to be down-converted to baseband before being applied to the reconditioning equalizer filter. The reconditioning equalizer filter could be performed in a digital or analog domain.

Abstract: In one embodiment, an amplifier system has a tap, a delay filter, a linearized amplifier, and a hybrid combiner. The tapped portion of an input signal is amplified by the amplifier, the untapped portion of the input signal is delayed by the delay filter, and the combiner combines the resulting amplified, tapped portion and the delayed, untapped portion to generate an amplified output signal. By re-combining the delayed, untapped portion of the input signal with the amplified, tapped portion, the power of the untapped portion is not lost, and the amplifier does not have to compensate for all of the distortion that would otherwise be associated with the total output power level. Such an amplifier system is applicable, for example, in upgrading an existing GSM cell site to support both GSM communications as well as UMTS communications without degrading GSM operations.

Abstract: An apparatus and method for a Time Alignment (TA) operation used by an Envelope Tracking (ET) Radio Frequency (RF) Power Amplifier (PA) that amplifies RF signals are provided. The ET RF PA has an input signal including complex, reference, and feedback signals. The apparatus includes a fast convolution unit for receiving the reference signal and the feedback signal, fore extracting respective envelopes of the reference signal and the feedback signal, for generating a cross-covariance vector for the reference signal envelope and the feedback signal envelope, a delay estimation unit for receiving the cross-covariance vector from the fast convolution unit, for determining peak values of the cross-covariance vector, for performing a fine time delay estimation, and for generating time delay settings according to the fine time delay estimation, and delay filters respectively delaying a timing of the reference signal and the feedback signal according to the generated time delay settings.

Abstract: A method of providing frequency dependent signal attenuation. An RF input signal is split into a first signal portion and a second signal portion. Discrete time filtering, a negative group delay and bandstop filtering are applied to the first signal portion to provide a filtered signal portion. The second signal portion is applied to a component, and a component output signal portion is received from the component. The component output signal portion is combined with the filtered signal portion to provide an RF output signal having frequency dependent attenuation.

Abstract: In an example embodiment, a method for bidirectional signal propagation comprises: a) sensing a voltage level of a first signal at a first port; b) coupling the first port to an output of an amplifier with a solid state switch if the voltage level of the first signal is less than a threshold voltage, whereby a second signal applied to a second port coupled to an input of the amplifier is propagated in a first direction from the second port to the first port; and c) bypassing the amplifier if the voltage level of the first signal is greater than the threshold voltage such that the first signal is propagated in a second direction from the first port to the second port.