DUAL-STAGE PREDISTORTION-BASED METHOD FOR CORRECTING ULTRA-WIDEBAND COMPLEX FORMAT VECTOR MODULATION ERROR

摘要

A dual-stage predistortion-based method for correcting an ultra-wideband complex format vector modulation error. A loop of the method comprises: a standard signal generating module, a stage I predistortion error compensator, a stage II predistortion compensator, an origin offset compensator, a transmission channel and a vector modulator. The stage I predistortion error compensator, by forming a filter predistortion, performs reverse cancelling with respect to amplitude and phase frequency response fluctuation characteristics of a wideband vector modulation error. The stage II predistortion error compensator corrects a modulation error that has undergone stage I predistortion balancing and that has wideband characteristics, that is, I/Q gain imbalance and a gain imbalance positive angle error in an entire working band. The origin offset compensator corrects a narrowband modulation error, namely, carrier leakage, by means of an analog device. Vector modulation errors having wideband characteristics are corrected by means of digital predistortion, thus effectively correcting a wideband complex format vector modulation error.