The present disclosure relates to signal sending circuits, signal receiving circuits, electronic apparatus, and base stations. One example circuit includes a signal pre-processing sub-circuit, a digital-to-analog conversion sub-circuit, an intermediate frequency power splitter, K frequency conversion phase-shift sub-circuits, and K antenna elements. An output end of the signal pre-processing sub-circuit is connected to an input end of the digital-to-analog conversion sub-circuit, an output end of the digital-to-analog conversion sub-circuit is connected to an input end of the intermediate frequency power splitter, an output end of the intermediate frequency power splitter is connected to input ends of the K frequency conversion phase-shift sub-circuits, and output ends of the K frequency conversion phase-shift sub-circuits are connected one-to-one to input ends of the K antenna elements.

This disclosure relates to variable-gain amplifiers that include degeneration circuits configured to adapt to a gain mode that is currently being implemented. For example, a variable-gain amplifier can operate in a plurality of gain modes to amplify a signal with different levels of amplification. The variable-gain amplifier can include a gain circuit configured to amplify a signal and a degeneration circuit coupled to the gain circuit. The degeneration circuit can include an inductor and a switching-capacitive arm coupled in parallel to the inductor. The degeneration circuit can operate based on a current gain mode to change an inductance for the variable-gain amplifier.

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 radio frequency module includes: a module board that includes a first principal surface and a second principal surface on opposite sides of the module board; a first power amplifier disposed on the first principal surface and configured to amplify a transmission signal in a first frequency band; a second power amplifier disposed on the first principal surface and configured to amplify a transmission signal in a second frequency band different from the first frequency band; and a switch disposed on the second principal surface and connected to an output terminal of the first power amplifier and an output terminal of the second power amplifier.

A DPD (1) includes: a polynomial structure including a pseudo-interpolation/sub-sample-shift processing unit (101) configured to operate at a sampling rate for sampling an input signal not upsampled in a previous stage of the DPD (1), pseudo-interpolate a sample point between sample points of the input signal, and shift the pseudo-interpolated sample point by a sub-sample and a multiplexer (109) configured to select a combination of a sub-sample shift amount; and an FIR filter (107) configured to be provided in a subsequent stage of the polynomial structure and include a sub-sample delay filter delaying a sample point of the input signal by a sub-sample. The DPD (1) compensates for distortion due to a sample point of the input signal and compensates for distortion due to a sub-sample point between sample points of the input signal for the DPD (1), by using the polynomial structure and the FIR filter (107).

Aspects of the disclosure relate to an apparatus for wireless communication. The apparatus may include a set of power detectors configured to generate a set of analog signals related to a set of output signal power levels of a set of transmit chains of a transmitter, respectively; an analog summer; a set of switching devices configured to send a selected one or more of the set of analog signals to the analog summer, and substantially isolated unselected one or more of the set of power detectors from the analog summer, wherein the analog summer is configured to generate a cumulative analog signal based on a sum of the selected one or more of the set of analog signals; an analog-to-digital converter (ADC) configured to generate a digital signal based on the cumulative analog signal; and a controller configured to control the set of switching devices.

Radio frequency (RF) acoustic wave resonator (AWR) filter circuits and methods. Embodiments essentially de-couple the stopband or notch characteristics of an RF filter from the passband characteristics. Accordingly, the de-coupled parameters can be individually designed to meet the specifications of a particular application. Partially-hybridized or fully-hybridized series-arm and parallel-arm AWR filter building blocks enable “de-coupled” RF filters having (1) wideband and low insertion loss passbands and (2) wideband deep notches (stopbands) with a specifically placed notch center frequency, without compromising the passband characteristics. The AWR filter building blocks include an inductance L that matches (resonates with) the electrostatic capacitance CO of the corresponding AWR within a desired passband. The resonance and anti-resonance frequencies of the building block AWRs are selected to be spaced apart from the specified passband in order to provide independent stopband or notch characteristics without substantially affecting the passband characteristics.

A radio frequency module includes: a module board that includes a first principal surface and a second principal surface on opposite sides of the module board; a first power amplifier configured to amplify a transmission signal in a first frequency band; a second power amplifier configured to amplify a transmission signal in a second frequency band different from the first frequency band; and a switch having a first pole connected to an input terminal of the first power amplifier and a second pole connected to an input terminal of the second power amplifier. The first power amplifier and the second power amplifier are disposed on the first principal surface, and the switch is disposed on the second principal surface.

A radio frequency (RF) multiplexer circuit is provided. The multiplexer includes a first circuit coupled between a first input terminal and a first output terminal. The first circuit is configured and arranged to transfer a first RF signal coupled at the first input terminal to the first output terminal as a first output signal when a first control signal is at a first logic value. The multiplexer includes a second circuit coupled between a second input terminal and the first output terminal. The second circuit is configured and arranged to transfer a second RF signal coupled at the second input terminal to the first output terminal as a second output signal having a gain higher than the gain of the second RF signal when the first control signal is at a second logic value.

An apparatus, method and system for transmission are described herein. For example, apparatus can include a synthesis engine, a power supply and a multiple input single output (MISO) operator. The synthesis engine is configured to generate amplitude control signals, phase control signals and power supply control signals based on command and control information. The power supply is configured to receive the power supply control signals and to generate a power supply signal. Further, the MISO operator is configured to generate an output signal with an amplitude or a phase controlled by at least one of the amplitude control signals, the phase control signals and the power supply signal.