Scintera Networks, Inc.

Spectrian Corporation

Armando C Cova

Qian Yu

Lance Todd Mucenieks

Frederic Roger

Adric Quade Broadwell

Emil James Crescenzi, Jr

Stephen J Foley

Majid Nemati Anaraki

Augustin P Chang

A performance monitor for generating a digital error signal based upon an RF input signal and an amplified RF output signal is provided. The monitor includes: a first analog-to-digital converter operable to digitize an in-phase (I) and a quadrature-phase (Q) version of the RF input signal responsive to a first clock signal to provide a first digital I signal and a first digital Q signal; a second analog-to-digital converter operable to digitize an in-phase (I) and a quadrature-phase version of the amplified RF output signal responsive to a second clock signal to provide a second digital I signal and a second digital Q signal; a first adaptive delay filter to delay the first digital I signal and the first digital Q signal to provide a first delayed complex signal according to a first delay; a second adaptive filter to delay the second digital I signal and the second digital Q signals to provide a second delayed complex signal according to a second delay; a complex gain matching adder operable to add a complex gain matching factor to a selected one of the delayed complex signals to provide a gain matched complex signal; and an adder to add the gain matched complex signal to a remaining one of the first and second delayed complex signals to provide the digital error signal.

Error signal formation for linearization

A pre-distorter is provided for distorting an RF input signal to provide a pre-distorted radio frequency (RF) input signal to an amplifier that provides an amplified RF output signal, wherein the RF input signal has an envelope. The pre-distorter includes: a radio-frequency signal processing circuit that distorts the RF input signal according to a polynomial of powers of the envelope, each power of the envelope being weighted by a corresponding pre-distortion weight; and a performance monitor operable to compare a version of the amplified RF output signal to a delayed version of the RF input signal to provide an error signal, wherein the performance monitor is configured to iteratively adapt the coefficients based upon a gradient of a cost function, the cost function being a function of the error signal.

Pre-distortion with enhanced convergence for linearization

A polynomial generator and memory compensator module is provided that includes: a first bank of delay filters for generating current and delayed versions of the envelope for an RF input signal and for the square of the envelope, a polynomial generator for generating polynomials using the current and delayed versions of the envelope, each polynomial being weighted according to pre-distortion weights; an adder for adding the polynomials to provide a pre-distortion signal for pre-distorting the RF input signal to provide a pre-distorted RF input signal such that a power amplifier amplifying the pre-distorted RF input signal provides an amplified RF output signal that reduces a non-linearity of the power amplifier; and a second bank of delay filters for generating delayed versions of the output signal, wherein the adder further adds the delayed versions of the output signal to the polynomials to provide the pre-distortion signal.

Linearization with memory compensation

A hybrid multicarrier RF power amplifier linearization architecture combines ACT and feed-forward amplifier stages to achieve high output distortion rejection and enhanced amplifier linearity. A carrier cancellation loop is coupled with a main RF power amplifier stage having parallel RF power amplifiers coupled via intermod-complementing predistortion paths. The carrier cancellation loop is coupled to a feed-forward loop containing a feed-forward RF power amplifier, to produce a composite amplified output signal having very reduced intermodulation products. Vector modulators in the main amplifier and feed-forward amplifier stages are controlled by a digital signal processor, using outputs from various monitoring subsystems, including pilot tone detection, correlator, distortion and power detector circuits.

High linearity multicarrier RF amplifier

An RF power amplifier linearization architecture contains main and auxiliary path RF amplifiers. A distortion-inverting circuit extracts the distortion component from the output signal of the main amplifier and combines it with a delayed sample of the RF input signal to drive an auxiliary path RF amplifier, via a predistorter. An output quadrature hybrid combines the output of the main and auxiliary path amplifiers. The cascading of the distortion-inverting circuit with the predistorter compensates for the non-linear behavior of the auxiliary path RF power amplifier thereby producing a composite signal at the output quadrature hybrid, in which RF carrier components from each amplifier combine constructively while distortion components cancel.

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Sunnyvale, CA, United States of America

Armando C Cova