US 6,111,462 AGranted

RF power amplifier linearization using parallel RF power amplifiers having intermod-complementing predistortion paths

OwnerLance T. Mucenieks, Charles S. Robertson +2inventors

InventorsLance T. Mucenieks, Charles S. Robertson, Brent L. Irvine, Nemy Salvador

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Abstract

An RF power amplifier linearization architecture has a pair of matched RF amplifiers, RF signal paths through which are intercoupled with a phase and amplitude measurement and predistortion mechanism. By selectively combining the RF output of a main path RF power amplifier with the RF input signal supplied to a parallel path RF power amplifier, the predistortion control mechanism of the invention predistorts the RF input signal applied to the parallel path amplifier, so that it includes the same modulated RF carrier component as that applied to the main path amplifier, as well as a complementary version of the intermodulation component of the output of the main path amplifier. The predistortion for each amplifier is controlled such that the resulting RF output signals produced by the matched amplifier pair will have the desired RF carrier modulation component but equal amplitude and phase-reversed intermodulation components. Combining these two matched amplifier outputs in a quadrature hybrid produces a composite signal, in which the desired amplified modulated RF carrier components produced by each matched amplifier constructively sum, while unwanted IMD components cancel.

Claims24

Dependent claims

An RF power amplifier arrangement comprising:

an RF input port to which an RF input signal is applied;
an RF output port from which an RF output signal is derived;
first and second RF signal processing paths coupled between said input and output ports and containing first and second matched RF power amplifiers having the same transfer function;
said first RF signal processing path including a first controlled RF signal vector modulator, that is controllably operative to adjust one or more parameters of a first RF input signal component applied to said first RF power amplifier;
said second RF signal processing path including a controlled RF signal vector modulator, that is controllably operative to adjust one or more parameters of a second RF input signal component applied to said second RF power amplifier, and an intermodulation distortion (IMD) extraction circuit coupled to an output of said first RF power amplifier and being operative to generate said second RF input signal component as a combination of said RF input signal and an IMD component present in an amplified RF output signal from said first RF power amplifier;
and
an output signal combiner coupled to outputs of said first and second RF power amplifiers and said output port, and being operative to produce said RF output signal as a composite RF output signal, in which amplify RF carrier components produced by each of said first and second matched RF power amplifiers constructively sum and IMD components produced thereby destructively combine.

4 more elements

An RF power amplifier arrangement comprising main and parallel RF signal processing paths coupled to an RF signal input port to which a modulated RF carrier signal is applied, said first main path including a main path predistortion circuit coupled to a main path RF power amplifier, said second parallel path including a parallel path predistortion circuit coupled to a parallel path RF power amplifier having a transfer function that is the same as that of said main path RF power amplifier, and an intermodulation distortion extraction circuit coupled to said main and parallel paths and being operative to extract an intermodulation distortion component present in an amplified RF output signal from said first RF power amplifier, and an RF signal processing path combiner that is operative to combine RF outputs of said main and parallel path amplifiers to produce a composite RF output signal in which amplified modulated RF carrier components produced by said main and parallel path RF amplifiers constructively sum and intermodulation distortion components produced thereby destructively combine.

Dependencies are inferred from the claim text.