Linear envelope tracking RF power amplifier with adaptive analog signal processing
AssigneeMotorola, Inc.
InventorsJoseph Staudinger, David A. Newman, Benjamin R. Gilsdorf
Life of this patent
Estimating the term…
Abstract
A linear envelope tracking radio frequency (RF) power amplifier having an adaptive analog signal processing circuit. The amplifier outputs a voltage which is sampled by the adaptive analog signal processing circuit. The adaptive analog signal processing circuit generates an error signal which varies the linearity of the power amplifier. In one embodiment, the error signal controls a modulator which in turn controls the supply voltage to the power amplifier. In another embodiment, the control signal varies a controller which in turn varies a load placed on the power amplifier. The load in turn varies in linearity of the amplifier.
Claims10
An apparatus for adjusting the output of a linear envelope tracking radio frequency (RF) system, comprising:
- a power amplifier, the power amplifier receiving an input signal and generating an RF output signal;
- a load device connected to the output of the power amplifier, the load device placing a load on the output of the power amplifier in accordance with a distortion of the output signal;
- a controller, the controller generating a control signal to the load device to select the load placed on the output of the power amplifier;
- and
- an distortion detection circuit, the distortion detection circuit generating a distortion signal for input to the controller, the distortion signal being determined in accordance with a gain compression of the RF output signal, wherein the controller varies the control signal in accordance with the distortion signal.
A method for adjusting the output of a linear envelope tracking radio frequency (RF) system, comprising the steps of:
- amplifying an input signal to generate an RF output signal;
- placing a load on the output of the power amplifier, the load being variable to vary the linearity of the power amplifier;
- selecting the load placed on the output of the power amplifier;
- and
- generating a distortion signal for varying the step of selecting the load, the error signal being determined in accordance with a distortion of the RF output signal, wherein the distortion signal varies the load placed on the output of the amplifier.
Dependencies are inferred from the claim text.