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FPGA‐based system for effective IQ imbalance mitigation of RF power amplifiers
Author(s) -
Nuñez Perez Jose Cruz,
Juarez Cazares Sergio Alberto,
Galaviz Aguilar Jose Alejandro,
Sandoval Ibarra Yuma,
Perez Pinal Francisco Javier,
Tlelo Cuautle Esteban
Publication year - 2020
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2746
Subject(s) - predistortion , amplifier , electronic engineering , field programmable gate array , quadrature amplitude modulation , baseband , linearity , computer science , transmitter , adjacent channel , engineering , cmos , channel (broadcasting) , telecommunications , bit error rate , computer hardware
Summary To provide an adequate signal integrity to a power amplifier (PA), we propose a digital system for the degradation at the transmitter path, and it is implemented on a field‐programmable gate array (FPGA) board. The proposed system offers the following features: A M ‐ary quadrature amplitude modulation (QAM) digital signal generation and in‐phase/quadrature (IQ) imbalance mitigation, and by default, it performs as a predistortion model extraction from PA‐measured data. The simulations and tests provided are performed to effectively verify the PA linearity by using 256‐QAM signals. The nonlinearities are predicted as a reliable solution for linearizing the PA from measurements of AM/AM and AM/PM conversion curves. The performance is evaluated in terms of linearity, computation complexity, and FPGA hardware synthesis according to a dependability compliance of digital signal processing. Finally, the model is validated with input/output data observations to linearize the model with a fitting normalized mean squared error (NMSE) of around − 35 dB, a spurious free dynamic range of 40 dBm, and an adjacent channel power ratio reduction by − 20 dBm, for a class‐AB broadband radio frequency PA GaN HEMT of 10 W working at 2.34 GHz.