The embodiments described herein include amplifiers that are typically used in radio frequency (RF) applications. Specifically, the amplifiers described herein include a phase distortion compensation circuit that can compensate for input impedance variations that could otherwise lead to reduced efficiency and power performance. In one specific embodiment, the phase distortion compensation circuit is used to compensate for input impedance variations in the peaking amplifiers of a Doherty amplifier. In such embodiments, the phase distortion compensation circuit can absorb the non-linear input impedances of the peaking amplifiers in a way that may facilitate improved phase maintenance between the carrier and peaking stages of the Doherty amplifier.

Some embodiments relate to a device, comprising an amplifier and a linearizer, the linearizer comprising a first transistor, the first transistor comprising a first terminal coupled to an input of the amplifier, a second terminal configured to be coupled to a DC supply voltage, and a control terminal configured to control a current flowing between the first and second terminals and configured to receive a DC bias voltage different from a voltage of the first terminal. Some embodiments relate to a device, comprising an amplifier, comprising an input, an output, and a first set of one or more transistors coupled between the input and the output, and a linearizer, comprising a second set of one or more transistors coupled between a DC supply voltage and the input of the amplifier, wherein the first set of transistors and the second set of transistors have a same topology.

A device to reduce distortion in an amplifier includes an input transistor configured to generate a voltage based on an input signal. The device further includes a diode connected transistor that is configured to sink the current. The diode connected transistor includes an output terminal, and a control terminal, where the output terminal is coupled to a control terminal. The device further includes a current source circuit that coupled to the control terminal. The device additionally includes an impedance element that coupled to the output terminal at a first node and to the control terminal and the current source circuit at a second node.

A device to reduce distortion in an amplifier includes an input transistor configured to generate a voltage based on an input signal. The device further includes a diode connected transistor that is configured to sink the current. The diode connected transistor includes an output terminal, and a control terminal, where the output terminal is coupled to a control terminal. The device further includes a current source circuit that coupled to the control terminal. The device additionally includes an impedance element that coupled to the output terminal at a first node and to the control terminal and the current source circuit at a second node.

A power amplifier and power amplification circuit are described herein. An illustrative power amplifier is disclosed to include an input terminal, a drive amplifier connected to the input terminal, and an impedance modulator having a capacitance that is adjusted inversely and proportionately relative to a signal output by the drive amplifier, wherein the impedance modulator provides a feedback loop between an output of the drive amplifier and the input terminal.

A radio frequency transmitter includes N transmit channels, where each transmit channel includes one nonlinear module, a primary correction circuit, coupled to each of N nonlinear modules that correspond to the N transmit channels, and configured to provide a primary correction signal for the N nonlinear modules, and N secondary correction circuits, where the N secondary correction circuits are coupled to the N nonlinear modules respectively, and each secondary correction circuit is configured to provide a secondary correction signal for a nonlinear module coupled to the secondary correction circuit.

Apparatus and methods for power amplifier distortion networks are disclosed. In one aspect, there is provided a power amplifier system including a power amplifier configured to amplify a radio frequency input signal. The power amplifier including an input configured to receive the radio frequency input signal and an output configured to generate an amplified radio frequency signal. The power amplifier system further includes a distortion network electrically coupled to either the input or the output of the power amplifier. The distortion network including a plurality of channelized resistors. The channelized resistors connected in series to either an input or an output of the power amplifier.

Disclosed is a configurable dual vacuum tube triode amplifier. The amplifier comprises two vacuum tube triodes and a user configurable switching component. The user configurable switching component can be positioned into at least a first position and a second position to modify an arrangement of the two vacuum tube triodes to provide varying tonal characteristics of the amplifier. Positioning the user configurable switching component in the first position arranges the two vacuum tube triodes in a cascode configuration to achieve a tonal characteristic of a vacuum tube pentode. Positioning the multi-position user switch in the second position arranges the two vacuum tube triodes in either a single vacuum tube triode configuration to achieve a tonal characteristic of a single vacuum tube triode operating alone or two vacuum tube triodes operating in a parallel configuration to achieve the tonal characteristics of two vacuum tube triodes operating in parallel.

A method for improving the linearity of a radio frequency power amplifier, a compensation circuit (307) for implementing the method, and a communications terminal with the compensation circuit (307). In the method, a compensation circuit (307) is connected between a base (a3) and a collector (b3) of a transistor of a common emitter amplifier (306), in order to neutralize the impact of a variation in capacitance between the base (a3) and the collector (b3) of the transistor (306) according to a radio frequency signal. No additional direct-current power consumption is needed, and degradation in performance of other radio frequency power amplifiers can be avoided. The corresponding compensation circuit (307) can be easily integrated with a main amplification circuit, without affecting other performance of the main amplification circuit, and provides high adjustability.

A radio frequency (RF) amplifier circuit includes a field effect transistor (FET) (e.g., a FET belonging to a III-V FET enhancement group), where the FET includes a gate terminal coupled to an RF input node. The circuit further includes a prematch and biasing network coupled between a bias voltage node and the RF input node. The prematch and biasing network includes a nonlinear gate current blocking device configured to block a current from flowing between the bias voltage node and the RF input node.