Techniques are disclosed implementing a tunable transformer with additional taps in at least one of the three coils. The tunable transformer enables the resonant frequency within RF transceiver matching networks to be adjusted without substantially impacting the output power at resonance. The tunability of the transformer is partially driven by the insertion of additional coils within the transformer, which are selectively switched and may be further coupled with a tunable capacitance. The tunability of the transformer is further driven via the use of at least one multi-tap transformer coil, which allows electronic components to be coupled to different coil taps to thereby facilitate an adjustable DC inductance. Doing so counteracts changes in mutual inductance between the non-switched coils, and facilitates the stabilization of output power with shifts in resonant frequency.

Methods and systems for power amplification with digital quantized power supply with multiple amplifiers are disclosed herein. In one embodiment, In one embodiment, a time-varying envelope signal is sampled, quantized and decomposed into several constituent signals that are individually amplified, and then combined to form a desired amplified version of the quantized time-varying envelope. Amplitude, phase and/or frequency characteristics of one or more of the signals and supply voltages V.sub.dd and source current of one or more amplifiers are digital controlled based on the information provided by quantization process and slow and fast power control information. Amplitude, phase and/or frequency characteristics of one or more of the constituent signals to be amplified are controlled to provide the desired amplitude, phase, frequency, and/or spectral characteristics of the desired quantized version of the time-varying envelope signal.

A radio-frequency circuit includes a first power amplifier that amplifies a first transmission signal and outputs the first transmission signal amplified; and a second power amplifier that amplifies a second transmission signal different in frequency from the first transmission signal, and outputs the second transmission signal amplified. At least one of the first power amplifier or the second power amplifier switches from ET mode to APT mode, when (1) both the first power amplifier and the second power amplifier are outputting amplified transmission signals and (2) output power of at least one of the first power amplifier or the second power amplifier is greater than a first threshold power.

The invention relates to a variable gain system, particularly for optical receiver systems, having: an input for an electronic signal, at least two variable gain amplifiers, and an output for an amplified electrical signal, wherein the at least two variable gain amplifiers are connected in parallel to the input and the output aggregates the signals of the at least two variable gain amplifiers.

This application provides a power amplification apparatus, a beamforming system, a transmitter, and a base station. The apparatus includes a power amplifier that amplifies a first signal, a power supply, and a power supply modulator that controls, based on an envelope signal corresponding to the first signal, an operating voltage provided by the power supply to the power amplifier. The apparatus is further configured to amplify a second signal. The first signal is generated based on the part of a target amplified signal whose amplitude falls within a preset amplitude range. The second signal is generated based on the part of the target amplified signal whose amplitude falls beyond the preset amplitude range.

In one embodiment, an apparatus includes: a digital baseband circuit to receive a digital baseband signal and output a first digital baseband signal and a second digital baseband signal, the second digital baseband signal comprising a scaled version of the first digital baseband signal; a first transmitter signal path coupled to the digital baseband circuit to process the first digital baseband signal and output a first radio frequency (RF) signal; a second transmitter signal path coupled to the digital baseband circuit to process the second digital baseband signal and output a second RF signal; a first power amplifier coupled to the first transmitter signal path to amplify the first RF signal and output an amplified first RF signal; and a second power amplifier coupled to the second transmitter signal path to amplify the second RF signal and output an amplified second RF signal.

A sensor assembly including a capacitive sensor, like a microelectromechanical (MEMS) microphone, and an electrical circuit therefor are disclosed. The electrical circuit includes a first transistor having an input gate connectable to the capacitive sensor, a second transistor having an input gate coupled to an output of the first transistor, a feedforward circuit interconnecting a back-gate of the second transistor and the output of the first transistor, and a filter circuit interconnecting the output of the first transistor and the input gate of the second transistor.

A data transmitter includes: a plurality of parallel driver slices, a first slice of the plurality of parallel driver slices having a first signal generator circuit with a first transistor coupled to a data signal and in series with a second transistor coupled to a first bias signal; and a first bias circuit including a third transistor and a fourth transistor in series with a first current source, the first bias circuit further including a first operational amplifier (op amp) having a first input coupled to a first reference voltage and a second input coupled between the fourth transistor and the first current source, an output of the first op amp configured to provide the first bias signal to the second transistor and to the third transistor.

A multichannel transmission system which includes a calibration functionality that allows precise calibration of the frequency conversion chains and of the multiport amplifier of the system to be performed without interruption of service. The proposed calibration makes it possible to correct the defects over the entire frequency band of the system.

A power amplifier includes: at least two first bridge type amplifying circuits and at least two second bridge type amplifying circuits; the negative pole of the first load of each first bridge type amplifying circuit is respectively coupled to the positive stage of the second load of each second bridge type amplifying circuits through a gating circuit. When both a first input signal input into one of the at least two first bridge type amplifying circuits and a second input signal input into one of the at least two second bridge type amplifying circuits are less than a preset threshold, the gating circuit is turned on, so that the one of the at least two first bridge type amplifying circuits and the one of the at least two second bridge type amplifying circuits can share load current by the gating circuit.