Design and Optimization of Flexible and Coding Efficient All-Digital RF Transmitters

All-digital transmitters are getting increased attention due to its closer proximity to the ideal software-defined radio (SDR) transmitter. In this paper we propose a new transmitter architecture that addresses two key limitations of current approaches, namely, the poor coding efficiency and the high quality factor requirements of the RF output reconstruction filter that significantly limit the practical usability and dissemination of these new flexible RF transmitters. The proposed architecture combines a maximum coding efficiency of 79.3% and a signal-to-noise ratio (SNR) of 50 dB, while maintaining the high flexibility inherent to the all-digital transmitters and where the RF output carriers operating in the microwave frequency range are generated inside a single field-programmable gate array (FPGA) device. The obtained results also show the feasibility and potential of using FPGA-based architectures for implementing digital RF transmitters.