Time-advanced phase correction in a power amplifier circuit is disclosed. The power amplifier circuit includes a power amplifier that amplifies an analog signal, which is associated with a time-variant power envelope, based on a modulated voltage. To correct phase misalignment between the modulated voltage and the time-variant power envelope, the power amplifier circuit also includes a phase correction circuit that generates a modulated phase correction voltage based on the modulated voltage to thereby cause a phase change in the analog signal. However, the modulated phase correction voltage can lag behind the modulated voltage in time due, in part, to inherent group delay of the phase correction circuit. As such, the power amplifier circuit further includes a time advance circuit to time advance the modulated phase correction voltage to thereby realign the modulated phase correction voltage and the modulated voltage in time for an optimal phase correction in the analog signal.

According to various embodiments, an electronic device may include: a communication processor, a radio frequency (RF) integrated circuit (RFIC) configured to receive a signal output from the communication processor and to modulate the signal into an RF signal, a power management circuit, a first power amplifier configured to amplify an RF signal output from the RFIC based on power supplied from the power management circuit, a second power amplifier configured to amplify the RF signal output from the RFIC based on the power supplied from the power management circuit, at least one capacitor connected in parallel to a power supply terminal of the first power amplifier, and at least one switch connected between the power supply terminal and the at least one capacitor, wherein the communication processor is configured to: identify a power amplification mode based a frequency band of the RF signal, and control the at least one switch by outputting a control signal corresponding to the identified power amplification mode.

An electromyography (EMG) device according to an aspect of the present disclosure includes a main circuit board having opposing first and second faces. A plurality of first connectors of a first type are provided on the first face, and a plurality of input contacts are provided on the second face. An EMG circuit is provided on the main circuit board. The EMG circuit is configured to utilize the input contacts as inputs to obtain an EMG input signal, and process the EMG input signal to provide an EMG output signal that is based on, but different from, the EMG input signal. For each of the input contacts, there is no conductive path directly between the input contact and any of the first connectors.

A power amplifier circuit includes a first power supply terminal electrically connected to a first power amplifier; a second power supply terminal electrically connected to a second power amplifier subsequent to the first power amplifier; a first external power supply line configured to electrically connect a power supply circuit configured to output a power supply potential corresponding to an amplitude level of a high-frequency input signal and the first power supply terminal; and a second external power supply line configured to electrically connect the power supply circuit and the second power supply terminal. An inductance value of the first external power supply line is higher than an inductance value of the second external power supply line.

A method for powering an audio amplifier includes receiving an input audio signal in an audio signal processor, delaying the input audio signal in the audio signal processor to generate a delayed audio signal, predicting a power demand estimate by analyzing the input audio signal to calculate the power demand estimate in the audio signal processer, and selecting, by the audio signal processor, power conversion settings for a DC to DC converter on the basis of the power demand estimate. The method further includes supplying power input to the DC to DC converter, converting the power input in accordance with the power conversion settings to provide a power output, powering the audio amplifier using the power output, and supplying the delayed audio signal to the audio amplifier from the audio signal processor to generate an amplified audio signal.

An envelope tracking (ET) power amplifier apparatus is provided. The ET power amplifier apparatus includes an amplifier circuit configured to amplify a radio frequency (RF) signal based on an ET voltage and a tracker circuit configured to generate the ET voltage based on an ET target voltage. The ET power amplifier apparatus also includes a control circuit. The control circuit is configured to dynamically determine a voltage standing wave ratio (VSWR) change at a voltage output relative to a nominal VSWR and cause an adjustment to the ET voltage. By dynamically determining the VSWR change and adjusting the ET voltage in response to the VSWR change, the amplifier circuit can operate under a required EVM threshold across all phase angles of the RF signal.

Systems, circuitries, and methods for predistorting a digital signal in a transmit chain based on a predistortion function are provided. A method includes shifting a center frequency of an input signal by an offset to generate an adapted signal; predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal; reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal; and causing transmission of the predistorted signal by a transmit chain.

An electronic device includes a network monitor configured to acquire network environment information related to a radio frequency (RF) transmission signal; a transceiver configured to generate an envelope signal of the RF transmission signal; a transmission (Tx) module including a power amplifier for receiving the RF transmission signal from the transceiver and amplifying the RF transmission signal; and an envelope tracking (ET) modulator configured to receive the envelope signal from the transceiver and to provide a bias of a power amplifier to correspond to the envelope signal, wherein the ET modulator determines a magnitude of the bias of the power amplifier based on the network environment information acquired by the network monitor.

An envelope tracking method and device are provided. The envelope tracking method includes: acquiring, by a boost circuit, a target envelope tracking input current signal, and transmitting, by the boost circuit, the target envelope tracking input current signal to an amplifier circuit, where the amplifier circuit includes an operational amplifier and a feedback network, and the operational amplifier operates in a mode of floating ground; and performing, by the amplifier circuit, closed-loop conversion and amplification on the target envelope tracking input current signal and outputting, by the amplifier circuit, an envelope tracking output voltage.

A difference between subsequent measures of a second signal when a first signal crosses a threshold value can be used to estimate a delay between the first and second signal. The delay can be used to compensate for delays between an envelope power supply signal and a radio frequency (RF) input signal.