نویسندگان
1 تربیت مدرس، دکترای برق الکترونیک
2 دانشگاه تربیت مدرس، استاد دانشکده مهندسی برق و کامپیوتر
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
This paper presents envelope shaping and linearization techniques for envelope-elimination-and-restoration (EER) power amplifiers in wideband applications. Although the EER technique can enhance the efficiency of the power amplifier, its use in the OFDM-based systems with stringent mask and EVM requirements needs additional considerations, especially for wideband signals. To satisfy the required spectral mask and EVM of the transmitter, two digital pre-distortion algorithms are implemented and compared for linearization of the EER system. To increase the output power and efficiency, envelope clipping technique is proposed for the EER transmitter. The imposed nonlinearity caused by the clipping can be reduced by the pre-distortion. Further, time delay mismatch between amplitude and phase paths is investigated and a solution is proposed for its alleviation. For accurate and realistic results, these techniques are tested under interlock operation of digital, analog, and RF segments of the EER system for 802.16e WiMAX signal. The co-simulation results show that the proposed techniques can enhance the efficiency and output power while satisfying the required linearity of the transmitter.
کلیدواژهها [English]
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