A Five-Level RF-PWM Method with Third and Fifth Harmonic Elimination for All-Digital Transmitters

Abstract

An appropriate pulse-coding algorithm is the key to achieving an efficient switched-mode power amplification in all-digital transmitters. A five-level RF-PWM method with third and fifth harmonic elimination is proposed to relax the requirements of the filter and to reduce the control complexity of the SMPA for all-digital transmitters. By controlling the pulse width and the center position of three-level sub-pulses, third and fifth harmonic elimination is achieved. Meanwhile, the control complexity of the SMPA is reduced by the decrease in the output-signal-level number. Finally, the feasibility of the method is verified by simulation. For the 16QAM signal with a carrier frequency of 200 MHz, the proposed method can achieve third harmonic suppression of −46.24 dBc and fifth harmonic suppression of −54.05 dBc when coding efficiency reaches 77.51%.

An Outphasing Architecture Based on Parallel Radio Frequency–Pulse Width Modulation Method for All-Digital Transmitter

“…In recent years, the development trend of wireless communication has been to utilize software radio to achieve functions of the digital domain for a transmitter. The alldigital transmitter (ADTx) has developed rapidly, and its flexible reconfigurable and programmable performance meets the design requirements of the high efficiency of the transmitter and the demand of SDR technology [1,2]. ADTx implements radio frequency (RF) functions such as up-conversion and pulse encoding in the digital domain and is mainly composed of a direct digital radio frequency modulator (DDRFM), a switchedmode power amplifier (SMPA), and the tuning filter.…”