A Cartesian Sigma-Delta transmitter architecture

This paper proposes a transmitter architecture that enables high peak to average power ratio (PAPR) signals transmission with good linearity and efficiency. The architecture is based on the principle of transforming a non constant envelope modulated signal in a constant one using low-pass Sigma-Delta (SigmaDelta) modulators on the in-phase and quadrature baseband signal components. This conversion enables the use of a switched mode power amplifier which increases the transmitter power efficiency. Cartesian SigmaDelta architecture performances have been studied and compared to those obtained with a polar Sigma Delta transmitter architecture.