On the behavior of the LINC transmitter

Abstract

The effects of RF signal processing impairments in a LINC transmitter are analyzed. A theoretical analysis of the effect of three different kinds of imbalances between the parallel signal paths in a real LINC transmitter is presented. These include the power gain and delay (or phase) imbalance between the two RF paths and the different nonlinear characteristics of both RF power amplifiers. In all cases analytical expressions have been obtained in order to evaluate the effect of the imbalances on the performance of the LINC transmitter. The gain and the phase imbalance between both power amplifiers appears as a serious constraint on performance. The system degradations are described in terms of the undesired response rejection at the system output. A classical two tones test has been used.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>