Polar loop transmitter for GSM/GPRS/EDGE

Abstract

An EDGE transmitter using a nonlinear GSM type PA is presented. It is based on a polar loop architecture that employs separate feedback control of the amplitude and the phase of the output signal. With this approach, the problems with AM-to-PM as well as AM-to-AM of the nonlinear PA are essentially eliminated. There is no mode change between GMSK and EDGE, and the transmitter operates seamlessly in multi-slot EGPRS. The polar modulation transmitter meets all the GSM type approval requirements for both EDGE and GMSK in the quad band (850/900/1800/1900 MHz). It is part of an RF subsystem which is in production.