Tunable delta-sigma modulator for agile all-digital transmitters

Fully digital transmitters have been thoroughly explored over the last few years to develop a novel type of agile, reconfigurable, multi-band, multi-standard and highly-efficient transmitters. However, with regard to agility and reconfigurability, current state-of-the-art approaches are still very restrictive. This paper proposes a new architecture based on a tunable delta-sigma modulator suitable for designing RF fully digital transmitters either in single-carrier or in dual-carrier scenarios. A 2-path polyphase decomposition was also developed to optimize some figures of merit, such as SNR and EVM, and to demonstrate the scalability of this type of modulator. This novel architecture has been successfully implemented and validated on an FPGA-based transmitter for single- and dual-carrier scenarios.