Circuits and methods for using in parallel amplification and signal combining are described herein. A circuit uses a digitally controlled multistage cascade combiner, a digital phase and drive signal amplifier controller and a digital combiner controller circuit with N parallel signals with constant amplitudes belonging to an alphabet with M discrete values and discrete phases feeding it. The signals resulting from N power amplifiers (PAs) have also constant amplitudes belonging to an alphabet with N discrete values and discrete phases prior to being fed to the multistage combiner. A digital combiner controller circuit generates digital control information to activate, or deactivate, the outputs of the PAs, where a set of digital control signals generated in digital combiner controller are used to control sets of switches, where the signals can be activated at the combiner's inputs, according to their power and phase values. The digital control information ensures that only in-phase signals are combined in the active combiner stage and any difference among the inputs of the combiners is always minimized. Both digital combiner controller and digital drive signal amplifier controller, share information about the signals not to be fed to the multistage combiner, so that PAs drive signals can also be powered off under these circumstances. In provide high efficiency amplification the signal amplifiers employed before the combining stage may be of switched or current source type.

A radio frequency (RF) receiver includes a radiating element, a chip and a phase shifting circuit. The radiating element is arranged to receive an RF input signal to produce a plurality of electrical signals. The chip includes an amplifier circuit. The amplifier circuit is configured to receive a plurality of phase shifted signals from a plurality of input terminals respectively, and amplify the phase shifted signals to generate an RF output signal. The phase shifting circuit is located outside the chip, and coupled to the output terminals and the input terminals. The phase shifting circuit is arranged to phase shift the electrical signals and accordingly generate the phase shifted signals. The phase shifting circuit and the radiating element are formed on a same substrate.

Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker is provided for a power amplifier that amplifies an RF signal. The envelope tracker includes an error amplifier that controls a voltage level of a power amplifier supply voltage of the power amplifier based on amplifying a difference between a reference signal and an envelope signal indicating an envelope of the RF signal. The envelope tracker further includes a multi-level switching circuit that generates an error amplifier supply voltage based on sensing a current of the error amplifier, and uses the error amplifier supply voltage to power the error amplifier.

The present disclosure is a novel utility of a software defined radio (SDR) based Distributed Antenna System (DAS) that is field reconfigurable and support multi-modulation schemes (modulation-independent), multi-carriers, multi-frequency bands and multi-channels. The present disclosure enables a high degree of flexibility to manage, control, enhance, facilitate the usage and performance of a distributed wireless network such as flexible simulcast, automatic traffic load-balancing, network and radio resource optimization, network calibration, autonomous/assisted commissioning, carrier pooling, automatic frequency selection, frequency carrier placement, traffic monitoring, traffic tagging, pilot beacon, etc.

An envelope tracking (ET) power amplifier apparatus is provided. The multi-mode power amplifier apparatus includes a pair of power amplifiers configured to amplify a radio frequency (RF) signal(s) and an output circuit that outputs the amplified RF signal(s) to a signal output(s). In examples disclosed herein, a control circuit can cause the multi-mode power amplifier apparatus to operate in different power management modes by changing a load impedance coupled to the signal output(s). In a non-limiting example, the control circuit can change a power management mode of the multi-mode power amplifier apparatus based on modulation bandwidth of the RF signal(s). As a result, the multi-mode power amplifier apparatus can operate across a wide range of modulation bandwidth without compromising efficiency and performance.

Systems and apparatuses are disclosed that include an RF generator configured to generate RF signals having a wavelength. Amplifiers are configured to receive and amplify the RF signals from the RF generator and are separated from each other by a separation distance in a range between about 0.2 times the wavelength and about 10.0 times the wavelength. A power management system is configured to control one or more of the amplifiers based on information received that is associated with the RF signals.

An improved amplification of multiband signals for an uplink, in particular a satellite uplink is provided. For this purpose, multiple signals for separate frequency bands may be provided to a number of two or more uplink converters. The output of each uplink converter is amplified by a separate amplifier and the separately amplified signals are combined to obtain an amplified multiband uplink signal. In particular a waveguide combiner may be used for combining the amplified signals.

Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker is provided for a power amplifier that amplifies an RF signal. The envelope tracker includes an error amplifier that controls a voltage level of a power amplifier supply voltage of the power amplifier based on amplifying a difference between a reference signal and an envelope signal indicating an envelope of the RF signal. The envelope tracker further includes a multi-level switching circuit that generates an error amplifier supply voltage based on sensing a current of the error amplifier, and uses the error amplifier supply voltage to power the error amplifier.

Circuits and methods for using in parallel amplification and signal combining are described herein. A circuit uses a digitally controlled multistage cascade combiner, a digital phase and drive signal amplifier controller and a digital combiner controller circuit with N parallel signals with constant amplitudes belonging to an alphabet with M discrete values and discrete phases feeding it. The signals resulting from N power amplifiers (PAs) have also constant amplitudes belonging to an alphabet with N discrete values and discrete phases prior to being fed to the multistage combiner. A digital combiner controller circuit generates digital control information to activate, or deactivate, the outputs of the PAs, where a set of digital control signals generated in digital combiner controller are used to control sets of switches, where the signals can be activated at the combiner's inputs, according to their power and phase values. The digital control information ensures that only in-phase signals are combined in the active combiner stage and any difference among the inputs of the combiners is always minimized. Both digital combiner controller and digital drive signal amplifier controller, share information about the signals not to be fed to the multistage combiner, so that PAs drive signals can also be powered off under these circumstances. In provide high efficiency amplification the signal amplifiers employed before the combining stage may be of switched or current source type.

Switch circuits for electrical power are formed of a hybrid coupler configured to receive a signal as an input, and output first and second pulsed wave signals along first and second signal paths, respectively; in a plurality of time frames, wherein the phases of the first and second pulsed wave signals along first and second signal paths are aligned. The switch circuits may be incorporated in time folding power circuits as an exemplary application.