Nonideal effects of reconstruction filter and I/Q imbalance in digital predistortion

Abstract

Digital predistortion linearization results are often degraded by nonideal factors in the transmitter chain. Among them, the gain ripple and phase delay of the analog reconstruction filter and the gain and phase imbalance of quadrature modulator are the major sources of linearizer performance degradation. The paper studies these effects and presents general guidelines for filter selection and imbalance compensation to maximize the predistortion performance.