Harmonic Elimination Method of RF-PWM Based on Phase-Shift Control and MPWM for All-Digital Transmitters

In this paper, a novel radio frequency pulse width modulation (RF -PWM) based on phase-shift control and mapping pulse width modulation (MPWM) is proposed. This method decomposes the modulated signal into two phase-modulated constant envelope signals by means of phase-shift control. The phase-modulated signals are directly converted to 3-level pulse waveforms after MPWM, and then a 5-level digital RF modulation signal will be fast generated through vector synthesis. In addition, the pulse width of the 5-level signal is controlled to eliminate specific subharmonic components, which can significantly reduce the design requirements of the filter. Compared with other PWM methods, it not only greatly reduces the size of the look-up table (L UT), but also improves the real-time and flexibility of all-digital transmitters (ADTx). Finally, the feasibility and effectiveness of this method are verified by the simulation.