A matching circuit includes first and second ports, an autotransformer, and first and second capacitors. The autotransformer includes a first terminal coupled to a first port, a second terminal coupled to a second port, and a common terminal coupled to a reference potential, and includes a series parasitic inductor and a parallel parasitic inductor. The first capacitor is coupled in shunt to the second terminal, and defines a low pass filter together with the series parasitic inductor. The second capacitor is coupled in series between the first port and the first terminal, and defines a high pass filter together with the parallel parasitic inductor.

An apparatus is provided that includes circuitry for decomposing an input signal to multiple substantially constant-envelope components and an outphasing path for each substantially constant-envelope component. The apparatus also includes a modulator for discrete phase control in each outphasing path, an amplifier in each outphasing path and a combiner for combining output signals from the outphasing paths. A system and method are also provided.

A radio frequency module includes: a module substrate including a first principal surface and a second principal surface opposite to each other; a plurality of external-connection terminals (e.g., a plurality of post electrodes) disposed on the second principal surface; a semiconductor component disposed on the second principal surface and including a first low-noise amplifier and/or a second low-noise amplifier; and a metal member set at a ground potential and covering at least part of a surface of the semiconductor component, the surface being opposite to a surface that faces the module substrate.

Disclosed is a digital radio-frequency transmitter, which includes a digital logic mixer, a digital power amplifier and an antenna, wherein an output terminal of the digital logic mixer is connected with an input terminal of the digital power amplifier; an output terminal of the digital power amplifier is connected to the antenna; the digital logic mixer is configured to perform logic mixing on baseband data and a radio-frequency local oscillator clock signal which are input into the digital radio-frequency transmitter to generate radio-frequency data; the digital power amplifier is configured to convert the radio-frequency data into an analog power signal; and the antenna is configured to transmit the analog power signal out. According to the digital radio-frequency transmitter of the present application, the circuit layout area and the circuit operation consumption can be effectively reduced.

Disclosed is a multi-band transmitter for transmitting a multi-band signal. The multi-band transmitter comprises: a pre-distortion unit including a first digital pre-distorter (DPD) which pre-distorts a first band signal and a second DPD which pre-distorts a second band signal discontinuous from the first band signal; a conversion unit which analog-converts the pre-distorted first band signal and the pre-distorted second band signal; an amplification unit including a first power amplifier (PA), which amplifies the analog-converted first band signal, and a second PA, which amplifies the analog-converted second band signal; and a feedback unit which digital-converts the amplified first band signal to feed the digital-converted first band signal back to the first DPD and digital-converts the amplified second band signal to feed the digital-converted second band signal back to the second DPD. The pre-distortion unit performs pre-distortion by using the fed-back first band signal and the fed-back second band signal.

Various embodiments of the disclosure disclose a method and apparatus, comprising: a communication processor; a radio frequency integrated circuit (RFIC) connected to the communication processor and outputting at least one of a first radio frequency signal, a second radio frequency signal, a third radio frequency signal, and a fourth radio frequency signal; a first circuit connected to the RFIC and including a first filter; a first radio frequency front end (RFFE) connected to the first circuit and including a first amplifier configured to amplify the first radio frequency signal and/or the third radio frequency signal; and a second RFFE including a second amplifier configured to amplify the second radio frequency signal and/or the fourth radio frequency signal output from the RFIC, wherein the communication processor is configured to control the first circuit to remove the fourth radio frequency signal induced to the first circuit through the first filter.

Exemplary embodiments are disclosed of current control circuits and methods of modulating supply current from a first device (e.g., a telematics control unit (TCU), etc.) to one or more second devices (e.g., one or more compensators, etc.). In an exemplary embodiment, a method includes modulating a supply current from a first device to a second device into different current values for reporting different information from the second device to the first device. An exemplary embodiment of a current control circuit includes a variable voltage source electrically coupled with a current source and a current sink. The current control circuit is configured to modulate the supply current from a first device to the second device into different current values for reporting different information from the second device to the first device.

The present invention discloses a communication apparatus having feedback calibration mechanism. A signal transmission circuit generates a RF analog signal according to a digital signal. A signal amplifying circuit amplifies the RF analog signal to generate an amplified analog signal. A LC impedance matching circuit transmits the amplified analog signal to the antenna to perform transmission. A feedback calibration circuit includes a feedback inductive circuit and a calibration circuit. A feedback inductive circuit is inductively coupled to the LC impedance matching circuit to receive the amplified analog signal to generate a feedback signal. A calibration circuit determines a distorted amount of the feedback signal relative to the RF analog signal to modify an operation parameter of at least one of the signal transmission circuit and the signal amplifying circuit to decrease the distorted amount.

A task processor has a low power connectivity processor and a high performance applications processor. Software processes have a component operative on a connectivity processor and a component operative on an applications processor. The low power connectivity processor is coupled to a low power front end for wireless packets and the high performance applications processor is coupled to a high performance front end. A power controller is coupled to the low power front end and enables the applications processor and high performance front end when wireless packets which require greater processing capacity are received, and removes power from the applications processor and high performance front end at other times.

A radio frequency circuit includes: a first filter having a first passband that corresponds to a portion of a frequency range of a first communication band allocated as a communication band for TDD; a second filter having a second passband that corresponds to a portion of the frequency range of the first communication band, the second passband being different from the first passband; a power amplifier that amplifies a transmission signal in the first communication band; a low-noise amplifier that amplifies a reception signal in the first communication band; and a switch that switches between connecting the first filter and the power amplifier and connecting the first filter and the low-noise amplifier, and switches between connecting the second filter and the power amplifier and connecting the second filter and the low-noise amplifier.