A transmitter with a DC detection circuit that can control when a modulator of the transmitter is active. When data is being transmitted, a tone introduced by a mixer in the transmit path is hidden by the data signal and has minimal effect on the transmit path. However, when there is no data, the tone can cause undesirable noise. A modulator may move the tone or noise outside of the transmitter's bandwidth. As the data can hide the tone, the DSM may only be needed when there is a DC signal. By activating the DSM only when a DC signal is detected, the extra power introduced by the modulator can be reduced while eliminating in-band noise.

An apparatus includes a radio-frequency (RF) circuit, which includes a power amplifier coupled to receive an RF input signal and to provide an RF output signal in response to a modified bias signal. The RF circuit further includes a bias path circuit coupled to modify a bias signal as a function of a characteristic of an input signal to generate the modified bias signal. The bias path circuit provides the modified bias signal to the power amplifier.

A transmission driver includes a pulse generator and a current mode logic driver. The pulse generator is configured to generate and output a first pulse signal by synchronizing at a falling edge time point of a first input signal, and generate and output a second pulse signal by synchronizing at a falling edge time point of a second input signal. The current mode logic driver is configured to output a pre-emphasis signal to which pre-emphasis technique has been applied by changing a first load resistance value and a second load resistance value based on the first pulse signal and the second pulse signal, respectively.

Examples described herein include methods, devices, and systems which may compensate input data for nonlinear power amplifier noise to generate compensated input data. In compensating the noise, during an uplink transmission time interval (TTI), a switch path is activated to provide amplified input data to a receiver stage including a recurrent neural network (RNN). The RNN may calculate an error representative of the noise based partly on the input signal to be transmitted and a feedback signal to generate filter coefficient data associated with the power amplifier noise. The feedback signal is provided, after processing through the receiver, to the RNN. During an uplink TTI, the amplified input data may also be transmitted as the RF wireless transmission via an RF antenna. During a downlink TTI, the switch path may be deactivated and the receiver stage may receive an additional RF wireless transmission to be processed in the receiver stage.

A reader for medical implants includes an antenna and a transceiver chip connected with the antenna. The transceiver chip includes a power amplifier and a resistor. The power amplifier is connected with a reference voltage through the resistor and configured to produce a first communication signal with high frequency and transmit the first communication signal to the medical implants through the antenna. The medical implant receives the first communication signal and produces a second communication signal according to variation of parameters of the medical implant. The antenna is configured to receive the second communication signal. The power amplifier is further configured to vary a DC current which flows through the resistor according to the second communication signal and read signals of the medical implant according to variation of the DC current. The power amplifier is further configured to modulate the second communication signal into a low frequency signal.

A multi-radio access technology (RAT) envelope tracking (ET) amplifier apparatus is provided. The multi-RAT ET amplifier apparatus may be configured to enable concurrent communication of at least two radio frequency (RF) signals associated with at least two different RATs. Specifically, the multi-RAT ET amplifier apparatus includes an ET integrated circuit (IC) (ETIC) and a distributed ETIC (DETIC) configured to generate respective ET voltages for amplifying the two RF signals. In addition, the DETIC can be configured to utilize certain circuit(s) in the ETIC to help reduce a footprint of the DETIC. By amplifying the two different RF signals based on the respective ET voltages and sharing certain circuit(s) between the ETIC and the DETIC, it may be possible to improve overall efficiency and heat dissipation in the multi-RAT ET amplifier apparatus concurrent to reducing the footprint of the DETIC.

A digital predistortion linearization method is provided for increasing the instantaneous or operational bandwidth for RF power amplifiers employed in wideband communication systems. Embodiments of the present invention provide a method of increasing DPD linearization bandwidth using a feedback filter integrated into existing digital platforms for multi-channel wideband wireless transmitters. An embodiment of the present invention utilizes a DPD feedback signal in conjunction with a low power band-pass filter in the DPD feedback path.

Method and controller are disclosed for controlling a power amplifier in a radio transmitter. According to an embodiment, a nonlinearity of the power amplifier is determined. A supply voltage to the power amplifier is controlled based on the determined nonlinearity. A radio unit comprising the radio transmitter and a radio device comprising the radio unit are also disclosed.

A radio frequency module includes a radio frequency filter (10), and the radio frequency filter (10) includes a terminal (11), a terminal (12), an impedance element (Z) disposed in series on a path (13) connecting the terminal (11) and the terminal (12), and a parallel arm resonator (P) connected between a node (N) on the path (13) and a ground. The impedance element (Z) is a capacitor or an inductor, and a wiring length A.sub.1 between the node (N) and the parallel arm resonator (P) is shorter than a wiring length B.sub.1 between the impedance element (Z) and a terminal (terminal (11), for example) out of the terminal (11) and the terminal (12) having a shorter wiring length to the impedance element (Z).

An electronic device may include wireless circuitry with a processor, a transceiver, an antenna, and a front-end module coupled between the transceiver and the antenna. The front-end module may include one or more power amplifiers for amplifying a signal for transmission through the antenna. A power amplifier may include an amplitude modulation distortion compensation circuit coupled to the input of the power amplifier. The compensation circuit may include adaptive biasing transistors each having a first source-drain terminal coupled to the input of the power amplifier, a second source-drain terminal coupled to a supply voltage, and a gate terminal configured to receive a control voltage via a big resistor. The control voltage can be set to a voltage level so that the adaptive biasing transistors are only turned on when the voltage swing at the input of the power amplifier is relatively large.