High dynamic range AMAM predistortion

摘要

A predistortion function is evaluated with in-phase (I) and quadrature (Q) data words as arguments, while additive I and Q data words are generated in accordance with a comparison of the I and Q data words with a full scale value that generates maximum current in a digital power amplifier. The additive I and Q data words are added to the computed I and Q data words to produce predistorted I and Q data words. The predistorted I and Q data words are provided in a sequence to the digital power amplifier, which generates a corresponding radio-frequency (RF) analog signal.

主权项

1. An apparatus to receive a plurality of input in-phase (I) and quadrature (Q) data words provided from respective I and Q data channels, the apparatus comprising:
a digital power amplifier configured to generate a radio-frequency (RF) analog signal in accordance with a sequence of predistorted digital I and Q data words generated from the respective input I and Q data words and configured to generate maximum current when an input data word provided thereto is a full scale value; and a predistortion processor, comprising:
a multiplicative stage to evaluate a predetermined predistortion function with each of the input I and Q data words as arguments to generate computed I and Q data words;an additive stage to respectively generate additive I and Q data words, wherein the additive stage comprises a lookup table stored in a memory and containing the additive I and Q data words indexed by the respective input I and Q data words; andan adder to add the additive I and Q data words to the respective computed I and Q data words to produce corresponding predistorted I and Q data words that compose the sequence of predistorted digital I and Q words used to generate the RF analog signal.