A Modified All-Digital Polar PWM Transmitter

作者：Pasha Muhammad Touqir^*; Ul Haque Muhammad Fahim; Ahmad Jahanzeb; Johansson Ted

来源：IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS, 2018, 65(2): 758-768.

DOI：10.1109/TCSI.2017.2725980

• Software-defined radio (SDR)
• CMOS
• FPGA
• switch-mode PA (SMPA)
• outphasing
• polar pulse-width modulation (P-PWM)
• aliasing distortion
• image distortion
• LTE

This paper presents an all-digital polar pulsewidth modulated (PWM) transmitter for wireless communications. The transmitter combines baseband PWM and outphasing to compensate for the amplitude error in the transmitted signal due to aliasing and image distortion. The PWM is implemented in a field programmable gate array (FPGA) core. The outphasing is implemented as pulse-position modulation using the FPGA transceivers, which drive two switch-mode power amplifiers fabricated in 130-nm standard CMOS. The transmitter has an all-digital implementation that offers the flexibility to adapt it to multi-standard and multi-band signals. As the proposed transmitter compensates for aliasing and image distortion, an improvement in the linearity and spectral performance is observed as compared with a digital-PWM transmitter. For a 20-MHz LTE uplink signal, the measurement results show an improvement of up to 6.9 dBc in the adjacent channel leakage ratio.

• 出版日期2018-2