An adaptive RF polynomial predistorter IC for a feedforward power amplifier in a base station

摘要

An RF IC compensates for envelope frequency and/or carrier frequency dependence of third-order intermodulation products. Frequency dependence compensation reduces peak error power and thereby increases the efficiency of the error amplifier in a feedforward power amplifier arrangement. The predistorter may be arranged to provide third-order and fifth-order compensation terms (figure 14) or may be arranged to provide two third-order compensation terms acting with an equaliser delay line 1502 to counteract memory effect in the power amplifier. Predistorters respectively counteracting envelope frequency effects and carrier frequency effects may be cascaded (figure 16).