A highly integrated quad band low EVM polar modulation transmitter for GSM/EDGE applications

Abstract

A polar modulation transmitter, fabricated in BiCMOS technology, is presented. It uses an offset loop transmitter to achieve both GSM and EDGE phase modulation. For the 8PSK modulation, the amplitude information is reconstructed through the use of a saturated GSM power amplifier with collector voltage modulation. This solution does not require the use of SAW filters and RF isolators and maintains excellent EVM and good ACPR over a wide range of VSWR. This transmitter is part of a quad band GSM/EDGE highly integrated transceiver.