Abstract
A novel pulse encoding strategy for RF switch-mode power amplifier (SMPA) is proposed in this paper to achieve benefits of multi-level delta-sigma modulators (DSM) while alleviating challenges that multi-level DSM brings to SMPA. The pulse encoder consists of a multi-level delta-sigma modulators (DSM) followed by a level transformation module (LTM). Based on the equal-area criterion, LTM directly maps the multi-level DSM pulse train into a binary pulse train which enables a simple system configuration. The feasibility and effectiveness of proposed strategy are verified by numerical simulation and experimental measurement. Results show that, with a similar coding efficiency, the proposed strategy obtains more than 7 dB improvement in average in-band signal to noise ratio (SNR) compared to traditional two-level DSM.
Reconfigurable complex digital Delta-Sigma modulator synthesis for digital wireless transmitters