Evaluation of pulse modulators for all-digital agile transmitters

All-digital transmitters are gaining increased access over the last years, mainly due to white space technology needs. In this paper a new FPGA-based multichannel multimode transmitter architecture is presented. The new configuration includes improvements in PWM and ΣΔ Modulators, which are designed in order to optimize important figures of merit for RF transmitters as coding efficiency, usable bandwidth and SNR. The high flexibility of this architecture allows to easily change the frequency of the carriers as also the spectral masks, making it suitable for using in cognitive radio-based applications.