Abstract: In one embodiment, a signal processor for linearizing a non-linear circuit through pre-distortion of an input signal is provided that includes: a first coupler for extracting a version of the input signal, wherein a remaining portion of the input signal not extracted by the first coupler is provided to a first node; a mixer for multiplying the extracted version of the input signal with a pre-distortion signal to produce an additive signal, the pre-distortion signal having a relatively small or zero constant component such that the additive signal includes either no linear version of the input signal or a linear version of the input signal that has a lower power than the remaining portion of the input signal; and a second coupler to add the additive signal to the remaining portion of the input signal at the first node to form a pre-distorted input signal, whereby if the non-linear circuit processes the pre-distorted input signal to form an output signal, the output signal is a substantially linear function of

Abstract: Included is a radio transmission system comprising a plurality of power amplifiers (PAs); a plurality of Volterra Engine (VE) linearizers corresponding to the PAs; a plurality of feedback loops corresponding to the PAs; at least one digital hybrid matrix (DHM) coupled to the VE linearizers; and an analog hybrid matrix (AHM) coupled to the PAs, wherein the feedback loops are connected to the AHM and the VE linearizers but not to the PAs to reduce the number of feedback loops. Also included is a radio system comprising a plurality of PAs; a Volterra DHM (VDHM) coupled to the PAs; a plurality of feedback loops corresponding to the PAs; and an AHM coupled to the PAs, wherein the feedback loops are connected to the AHM but not to the PAs to reduce the number of feedback loops.

Abstract: A shared AMP includes: a transmission/reception processor section (TRX-B) for a second mobile communication system configured to perform frequency conversion processing on an inputted transmission baseband signal for a mobile communication system B, and to output a transmission radio frequency signal for the second mobile communication system; a power level adjuster section (VA) configured to adjust a power level of an inputted transmission radio frequency signal for a first mobile communication system; a combiner section (COM) configured to generate a transmission radio frequency signal, by combining the transmission radio frequency signal for the first mobile communication system outputted from the power level adjuster section (VA) and the transmission radio frequency signal for the second mobile communication system outputted from the transmission/reception processor section (TRX-B) for the second mobile communication system; and a common amplifier section (PA) configured to amplify a power level of the tr

Abstract: A power amplifier controller circuit controls a power amplifier based upon an amplitude correction signal indicating the amplitude difference between the amplitude of the input signal and an attenuated amplitude of the output signal. The power amplifier controller circuit comprises an amplitude control loop and a phase control loop. The amplitude control loop adjusts the supply voltage to the power amplifier based upon the amplitude correction signal. The amplitude loop may include a variable gain amplifier adjusting the amplitude of the input signal. The amplitude loop can include a compression control block which may be configured either to adjust the gain in the variable gain amplifier or the voltage from the power supply based upon the operating level of the other, in addition to being based upon the amplitude correction signal, thus providing a way of maintaining the depth beyond the PA's compression point and allowing a control of the efficiency of the RF power amplifier.

Abstract: A Solid State Power Amplifier (SSPA) for powering a single element of a multi-element antenna, the SSPA comprising: an RF amplifier, having a signal amplifying path that includes preamplifier, driver amplifier and a power output stage; an Electronic Power Conditioner (EPC) for providing a variable value of DC voltage for powering the power output stage of the RF amplifier; a control ASIC for receiving an input power signal of the RF amplifier for providing a voltage control signal to the EPC to determine the value of the DC voltage, the control ASIC addressing an EEPROM holding a collection of control words that define output values of a control output signal for varying values of said input power, such that the value of the DC voltage to the power output stage is varied so as to control the gain compression of the RF amplifier for varying values of input power in order to maintain constant amplifier linearity.

Abstract: In accordance with some embodiments of the present disclosure, a method may include digitally pre-distorting a digital baseband signal with an opposite phase of a C-IM3 distortion term such that the pre-distortion and C-IM3 distortion cancel each other out in a transmitter. The method may also include digitally conditioning the pre-distorted digital signal in order to provide a flat amplitude response of a composite filter comprising a baseband filter and a digital half-band filter of the transmitter, and to provide a linear phase response for the composite filter.

Abstract: Described is a space-time digital power amplifier that can be used to generate an arbitrary waveform for a carrier signal. The space-time digital power amplifier employs temporal modulation of transmit signals generated by an array of transmitter modules. The RF signals transmitted from the array are spatially combined through free space propagation to generate the desired waveform. Advantageously, no digital-to-analog conversion is required and upconversion is unnecessary. The digital power amplifiers for the transmitter modules can be combined in a single chip package. The space-time digital power amplifier enables high power efficiency to be realized using pulse-shaped waveforms thus eliminating any need for the power amplifiers to operate over a wider bandwidth with a spectrally unconfined waveform.

Abstract: Provided is a detector device including: an amplifier (AMP1) for amplifying a voltage of an input electric signal and outputting the amplified electric signal; a first detector circuit (Det1) for outputting a first detection signal having a current corresponding to the voltage of the input electric signal; a second detector circuit (Det2) for outputting a second detection signal having a current corresponding to the voltage of the input electric signal; and a current summing circuit (SUM1) to which the first detection signal and the second detection signal are input, for outputting a third detection signal having a current value obtained by summing current values of the first detection signal and the second detection signal, in which an input signal to be detected is divided into two, one of the divided signals being input to the first detector circuit (Det1) and the other of the divided signals being input via the amplifier (AMP1) to the second detector circuit (Det2).

Abstract: A wireless transmitter (100) comprises a signal generator (10) for generating a signal, an amplifier (50) for amplifying the signal, and a phase shifting circuit (20) coupled between the signal generator (10) and the amplifier (50) and arranged to shift the phase of the signal to cancel remodulation of the signal generator (10) by the amplified signal.

Abstract: The subject matter disclosed herein relates to changing at least one power state of a mobile station at least in part in response to information indicating a change in altitude from one or more sensors.

Abstract: The disclosure relates to an electronic differential amplification device integrated on a semiconductor chip. The device may include first and second transistors having respective source terminals connected to a first potential, and drain terminals to receive a first differential current signal. The device may include third and fourth transistors having respective source terminals connected to the first potential, and drain terminals to provide a second differential current signal to a load obtained by amplifying the first signal. The third and fourth transistors may have a respective gate terminal connected to the drain terminal of the first and the second transistors, respectively, in order to form current mirrors with the latter.

Abstract: A wireless communication device includes an RF transceiver configured to up convert a base band signal to a transmitting RF signal, a configurable matrix power amplifier circuit configured to amplify the transmitting RF signal to produce an amplified RF signal, and an antenna configured to transmit a wireless signal in response to the amplified RF signal.

Abstract: A mobile terminal includes: a battery supplying electric power; a voltage detection portion which detects the voltage of the battery; a function activation control portion which activates a predetermined function at a preset time; and a warning portion which, in reference to a predicted battery voltage at the preset time calculated by subtracting a predicted value of reduced voltage based on a consumed current until the preset time from a detected voltage detected by the voltage detection portion, raises a warning if the predicted battery voltage is smaller than the minimum voltage that is necessary for activating the predetermined function by the function activation control portion.

Abstract: One or more beamsteering matrices are applied to a plurality of signals to be transmitted via multiple antennas. The plurality of signals are provided to a plurality of power amplifiers coupled to the multiple antennas after applying the one or more beamsteering matrices to the plurality of signals. Signal energies are determined for the plurality of signals provided to the plurality of power amplifiers, and output power levels of the plurality of power amplifiers are adjusted based on the determined signal energies.

Abstract: In one embodiment, the present invention includes an apparatus having at least two gain stages to receive incoming signals and to output amplified signals, along with multiple regulators. More specifically, a linear regulator can be coupled to the first gain stage to provide a first regulated voltage to the first gain stage, and a switching regulator coupled to the second gain stage to provide a second regulated voltage to the second gain stage.

Abstract: A RF power amplifying device is constituted by a system of a balanced amplifier including first phase shifters, a first RF power amplifier, a second RF power amplifier, second phase shifters, and a power combiner. Transmitting power Pout is detected by a first power level detector connected to an output of the first RF power amplifier, a second power level detector connected to an output of the second RF power amplifier, and an adder. A level control signal from a level control circuit controls transmitting power in response to a transmitting signal with wanted power level and a detected signal of the adder.

Abstract: A Tx module includes a plurality of power amplification units, a plurality of matching circuit units configured as transformers having input ports connected to output ports of the plurality of power amplification units, respectively, and a plurality of harmonic filter units having input ports connected to output ports of the plurality of matching circuit units, respectively. At least one of the matching circuit units includes a plurality of primary windings connected to output ports of corresponding power amplifiers of the power amplification units and a secondary winding inductively coupled in common to the plurality of primary windings.

Abstract: A multi-band handheld communications device includes a transceiver including a transmitter having a transmit filter and a receiver having a receive filter, each of the transmit and receive filters having a bandpass region tunable across multiple bands, and a processor configured to select one of the multiple bands to operate the handheld communications device, and tune each of the transmit and receive filters based on the selected one of the multiple bands.

Abstract: Certain embodiments of the invention may be found in a method for integrated circuit supporting auto-sense of voltage for drive strength adjustment. The method may comprise detecting an input voltage received at an auto-sense pad integrated on a mobile multimedia processing (MMP) chip. The input voltage may be a power supply voltage of the peripheral device received during power-up of the MMP chip, power-up of the peripheral circuitry, and/or dynamically while the MMP is powered-up. The auto-sense pad may adjust drive strength of at least one other pad, which may be an output pad or a bidirectional pad, integrated on the MMP chip may be configured to operate using the determined output voltage. A rise time and/or fall time of signals output by the MMP chip may be varied by the adjustment of the drive strength.

Abstract: Communication equipment includes a circuit generating an RF input signal; a PA receiving a supply voltage, receiving the RF input signal, and providing an amplified version of the RF input signal as an output signal that is associated with an output power of the communication equipment; and an output circuit that includes an antenna for transmitting the output signal. The communication equipment also includes: a voltage detector circuit including sensing circuitry for sensing the supply voltage and a comparator for comparing the supply voltage to a first voltage threshold and generating a control signal when the supply voltage exceeds the first voltage threshold; and a disabling circuit coupled to the voltage detection circuit for disabling a portion of the communication equipment in response to the control signal to maintain output power of the communication equipment below a maximum output power level.

Abstract: A monolithic integrated circuit (IC), and method of manufacturing same, that includes all RF front end or transceiver elements for a portable communication device, including a power amplifier (PA), a matching, coupling and filtering network, and an antenna switch to couple the conditioned PA signal to an antenna. An output signal sensor senses at least a voltage amplitude of the signal switched by the antenna switch, and signals a PA control circuit to limit PA output power in response to excessive values of sensed output. Stacks of multiple FETs in series to operate as a switching device may be used for implementation of the RF front end, and the method and apparatus of such stacks are claimed as subcombinations. An iClass PA architecture is described that dissipatively terminates unwanted harmonics of the PA output signal.

Abstract: A feedback loop with an adjustable closed loop frequency response. The feedback loop contains adjustable pole (212, 213) and adjustable zero elements (220,221) for changing the pole and/or zero locations in the feedback loop's loop frequency response thereby changing the closed loop frequency response of the feedback loop. In one embodiment, the feedback loop is a Cartesian feedback loop suitable for use in a radio transmitter.

Abstract: A method and apparatus for transmission and reception of signals. An AlGaN amplifier is connected to an antenna. The AlGaN amplifier amplifies signals for transmission over the antenna and signals received from the antenna. Switches are controlled to provide the amplified signals for transmission to the antenna. The switches are also controlled to provide the signals received from the antenna to the AlGaN amplifier and to the receive path of the apparatus.

Abstract: Method and apparatus for configuring a transmitter circuit to support multiple modes and/or frequency bands. In an embodiment, a pre-driver amplifier (pDA) in a transmit (TX) signal path is selectively bypassed by a controllable switch. The switch can be controlled based on a mode of operation of the transmitter circuit. Further techniques are disclosed for selectively coupling the output of a driver amplifier (DA) to at least one of a plurality of off-chip connections, each connection coupling the DA output to a set of off-chip components.

Abstract: An RFIC includes an RF transmitter, that generates an RF signal to a power amplifier module that operates a selected one of a plurality of power amplifiers, based one or more control signals. A processing module generates the control signals based on a selected one of a plurality of modes, wherein the plurality of modes include a first wireless mode corresponding to the use of the RFIC in accordance with a first wireless standard and a second wireless mode corresponding to the use of the RFIC in accordance with a second wireless standard. A power management circuit generates a plurality of power supply signals including at least one power supply signal for selectively powering only the selected one of the plurality of power amplifiers, in response to the at least one control signal, wherein the power management circuit is bonded to a bottom of the RFIC so as to dissipate heat to a printed circuit board.

Abstract: A transmit amplifier stage operable to amplify a transmit signal comprises power amplifiers and switches. The power amplifiers include at least one fractional power amplifier operable to provide fractional power to amplify the transmit signal, where the fractional power is a fraction of the full power. A switch has a plurality of positions, where a position directs the transmit signal to a selected power amplifier.

Abstract: There is provided a modular amplifier structure that includes a plurality of parallel amplifier sub-units. Each amplifier sub-unit is configured to amplify a received payload signal under control of at least one received control signal. Outputs of the amplifier sub-units are applied to a combining circuit. The combining circuit is configured to combine the outputs of the plurality of amplifier sub-units to provide an amplified payload signal.

Abstract: Aspects of a method and system for amplitude calibration for polar modulation with discontinuous phase may include amplifying a signal via a plurality of amplifiers such that a combined gain of the plurality of amplifiers comprises a coarse amplitude gain, an amplitude offset gain and a calibration gain. A gain of one or more of the plurality of amplifiers may be adjusted to set the coarse amplitude gain, and a gain of one or more remaining ones of the plurality of amplifiers may be adjusted to set the amplitude offset gain and the calibration gain. The setting of the coarse amplitude gain, the calibration gain and/or said amplitude offset gain may be adjusted dynamically and/or adaptively.

Abstract: A transmission power control apparatus capable of reducing unnecessary transmission power that is consumed in transmission of pilot symbols. In the apparatus, a power control part establishes, based on a repetition number of a data signal, a transmission power value of a pilot signal. For example, the power control part establishes, based on an improved reception quality when data signals as replicated in accordance with the repetition number of a data signal are combined, a transmission power value of a pilot signal at a level required and sufficient for meeting a target value of the reception quality of the other end of communication. A power amplifying part amplifies the pilot signal in accordance with the established transmission power value.

Abstract: A radio terminal includes a first part that has a first gain switchable between first and second levels, a second part that continuously controls a second gain, and a control part. A first range of the combined gain of the first and second gains obtained by the second part with the first gain set at the first level and a second range of the combined gain obtained by the second part with the first gain set at the second level have at least an overlap. The control part switches the first gain from one to the other of the first and second levels if the combined gain is within the overlap and a change in the combined gain exceeds a predetermined value, or if the combined gain is within the overlap and the radio terminal is in a period of no transmission or reception in intermittent transmission or reception.

Abstract: A power amplifier for use in a transmitter enables linear in dB output power control capability with 2 dB step sizes.

Abstract: A high power amplifier having an automatic gain control circuit, the high power amplifier being coupled between the output end of an RF signal carrying coaxial cable and a transmitting antenna to automatically compensate for RF signal attenuation over the length of the coaxial cable.

Abstract: A RF power amplifying device is constituted by a system of a balanced amplifier including first phase shifters, a first RF power amplifier, a second RF power amplifier, second phase shifters, and a power combiner. Transmitting power Pout is detected by a first power level detector connected to an output of the first RF power amplifier, a second power level detector connected to an output of the second RF power amplifier, and an adder. A level control signal from a level control circuit controls transmitting power in response to a transmitting signal with wanted power level and a detected signal of the adder.

Abstract: A linear high powered integrated circuit amplifier includes a plurality of power amplifiers, balanced integrated circuit coupling, and a combining circuit. The balanced integrated circuit coupling couples a signal to the plurality of power amplifiers to the up-conversion module such that the power amplifiers amplify the signal to produce a plurality of amplified radio frequency (RF) signals. The combining circuit is operably coupled to combine the plurality of amplified RF signals to produce a high-powered amplified signal.

Abstract: Methods and apparatus for aligning output power levels of a transmitter having a power amplifier adapted to operate in first and second operational modes. According to an exemplary embodiment, the transmitter includes a power alignment circuit configured to execute a power alignment algorithm. The power alignment algorithm is operable to align an output power level of the power amplifier when configured in the first operational mode with an output power level of the power amplifier when configured in the second operational mode. When the power amplifier is switched from the first operational mode to the second operational mode, the power alignment circuit references a power table having power entries that ensure that the output power level in the second operational mode is aligned with the output power level in the first operational mode.

Abstract: A communications apparatus comprising a first antenna, a first serial configuration of a first power amplifier and a first matching network, a second serial configuration of a second power amplifier and a second matching network, a switching element for switchably selecting the first or the second serial configuration for supplying a signal to the first antenna, the first and the second power amplifiers supplying a respective first signal of a first power and a second signal of a second power different than the first power to the first antenna for transmitting and the first and the second matching networks presenting respective first and second impedances to the respective first and second power amplifiers, the first and the second impedances responsive respectively to a power-related parameter of the first and the second signals.

Abstract: A method for controlling alignment of a control loop in an amplifier system includes generating a pilot signal and injecting the pilot signal into the amplifier system. Any uncanceled pilot signal is detected at an output of the control loop. A frequency of the generated pilot signal is detected and is used in adjusting one or more parameters of the control loop. The adjusting is performed at a predetermined direction and with a predetermined step size. A frequency change in the pilot signal in response to the adjusting is detected. The control loop is iteratively aligned by controlling the adjusting based on the detected frequency change, and the step size is determined based on the detected frequency change.

Abstract: Some embodiments discussed relate to a method and apparatus, comprising a power amplifier module, a transceiver module coupled to provide a signal to an input of the power amplifier module. The transceiver module comprising an integrated temperature sensor to sense an instantaneous operating temperature of the transceiver and providing a first sensor output signal dependent upon the operating temperature, and an integrated voltage sensor to sense a transceiver supply voltage and generate a second sensor output signal dependent upon the instantaneous transceiver supply voltage, and a processor configured to receive the first and the second sensor output signals, provide a control signal to the power amplifier module to reduce the output power of the power amplifier responsive to the first and the second sensor output signals.

Abstract: A radio frequency (RF) front-end includes a plurality of power amplifier modules and a plurality of impedance matching circuits. Each of the plurality of impedance matching circuits includes an input connection and an output connection, wherein outputs of the plurality of power amplifier modules are coupled to corresponding input connections of the plurality of impedance matching circuits to provide a desired loading of the plurality of power amplifier modules and wherein the output connections of the plurality of impedance matching circuits are coupled together to add power of the plurality of power amplifiers.

Abstract: An amplifier includes: an input terminal configured to have an input signal of a center frequency f0 input; a dividing unit that divides the input signal; first through ith blocks configured to have the divided input signal transmitted; a combining unit that combines signals transmitted through the blocks; and an output terminal that outputs the signals combined by the combining unit. The nth block includes a nth former-stage resonator having a fundamental resonant frequency fn, a nth amplifying unit, a nth latter-stage resonator having the fundamental resonant frequency fn, and a nth phase adjusting unit. Each latter-stage resonator having a harmonic resonant frequency either fa or fb, satisfies relationship fa<2f1, fb>2f1, (fa+fb)/2=2f0 The phase adjusting unit is configured to reverse the phase of signals passing adjacent blocks and maintain all phase differences among signals of 2fn passing through the nth block in the coordinate-phase.

Abstract: A RF device such as a tower mounted amplifier (TMA), mast-head amplifier (MHA), or Tower Mounted Boosters (TMB) includes a housing having a plurality of cavities and an input and an output, the input being coupled to the antenna and the output being coupled to a base station. The housing includes a transmission path holding multiple coaxial resonators. The housing further includes multiple receive paths including at least one path having a plurality of cavities, each cavity containing a dielectric resonator. The metallic transmit resonator nearest the antenna input is coupled to the first dielectric resonator via a common resonant wire. The last dielectric resonator in the receive path is coupled to a first metallic resonator of a downstream clean-up filter via another common resonant wire.

Abstract: Data transmitter embodiments are provided which are particularly useful as interface devices for accurate and reliable transmittal of data from high-speed data system devices such as analog-to-digital converters. Transmitter embodiments have been found to provide excellent fidelity of data transfer at high data rates (e.g., 4 gigabits/second) while consuming only a portion of the power of many conventional transmitters and requiring only a portion of the layout area of these transmitters. Transmitter embodiments provide effective control of transmitter parameters such as matched impedances, data symmetry, common-mode level, data eye and current drain.

Abstract: In a particular embodiment, a circuit device includes a pulse edge control circuit to receive at least one pulse-width modulated (PWM) signal from a PWM source. The pulse edge control circuit is adapted to selectively apply a phase shift operation to the at least one PWM signal at integer submultiples of a frame repetition rate to produce at least one modulated PWM signal having a changed power spectrum. The pulse edge control circuit provides the at least one modulated PWM signal to at least one output of the pulse edge control circuit.

Abstract: An apparatus amplifies RF signals in a communication system by using a first directional coupler having at least two inputs and at least two outputs; at least two RF amplifiers, where an input of each RF amplifier is connected to a different one of the at least two outputs of the first directional coupler; and a second directional coupler having at least two inputs and at least two outputs, where each one of the at least two inputs is connected to an output of a different one of the at least two RF amplifiers. The at least two outputs of the second directional coupler are connected to at least two antennas, respectively.

Abstract: Disclosed herein are methods and apparatus for processing an input information signal having varying amplitude and phase to obtain an amplified output signal having the same amplitude and phase variation. In an exemplary method, an input information signal is decomposed into two pairs of constant-envelope component signals such that the vector sum of the first pair is orthogonal to the vector sum of the second pair, for desired signal amplitudes below a level corresponding to a pre-determined threshold. For desired signal amplitudes above this level, the input information signal is instead decomposed into two pairs of constant-envelope component signals such that the vector sum of the first pair is separated by less than ninety degrees from the vector sum of the second pair. The constant-envelope component signals may be amplified by highly-efficient non-linear amplifier elements and combined to obtain the amplified output signal.

Abstract: A base station (BS) and method to reduce RF interference by a carrier. The BS includes a first power amplifier (PA) that emits a first carrier, a second PA that emits a second carrier, a processor, and data storage containing program instructions. The BS is operable in a first state in which the first PA is on and the second PA is off and a second state in which the first and second PAs are on. Execution of the instructions while the BS operates in the first state cause the processor to determine that the BS receives a mobile station communication and cause the BS to operate in the second state, and while the BS operates in the second state, cause the processor to determine that no mobile stations are registered as being authorized to be served by the BS and cause the BS to operate in the first state.

Abstract: An RF transmitter with improved efficiency and good linearity decomposes an input AM signal into two signal envelopes with phased modulation at a phase angle ?. The transmitter has three principal embodiments. A first solution uses at least one added RF amplifier for each decomposed signal envelope with one or more amplifiers having a low gain compared to that of a high gain amplifier in another branch for the same signal envelope. A phase angle ?i is determined that corresponds to a switching on two of the 2n+2 total branches, n=0, 1, 2, . . . . A second solution uses the same general schematic architecture as the classic LINC system that requires only two RF amplifiers, but uses a different decomposition because the two RF amplifiers are used in their nonlinear zone. The decomposed signal envelopes can be variable. The amplified output signal allows the combiner to be used at 100% efficiency in major part of signal. The third solution combines the first and second solutions.

Abstract: A current canceling CMOS variable gain amplifier includes a first leg and a second leg. The first leg has a first input line, a first output line, a first ON transistor, a first control transistor and a first subtracting transistor. The second leg has a second input line, a second output line, a second ON transistor, a second control transistor and a second subtracting transistor. The second input line can provide a second input current. The second output line can provide a second output current. The first input line is arranged to provide a first input current to each of the first ON transistor, the first control transistor and the first subtracting transistor. The second input line is arranged to provide a second input current to each of the second ON transistor, the second control transistor and the second subtracting transistor. The first output line is in electrical connection with each of the first ON transistor, the first control transistor and the second subtracting transistor.

Abstract: Provided is a transmission output control apparatus including: a level control circuit operable to adjust a level of an inputted signal; a power amplifying circuit including a plurality of amplifying stages and being operable to amplify the signal whose level has been adjusted by the level control circuit; an antenna operable to transmit the signal amplified by the power amplifying circuit; a memory unit operable to prestore a plurality of control signals; a control signal generating unit operable to select and extract, from the memory unit, one of the control signals that is in accordance with a transmission level instructed by a base station, and supply the extracted control signal to the level control circuit; and a detection unit operable to detect a signal at a midway amplifying stage of the power amplifying circuit, where a transmission level of the level control circuit is monitored according to an output of the detection unit.

Abstract: Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.