Extraction of Optimal Operation Condition of QAM Envelope Tracking System using Combined Cost Function of Bandwidth and Efficiency
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초록
In this paper, we suggest a combined cost function to find out the optimal operation of an envelopetracking system, and evaluated its performance with Quadrature Amplitude Modulation (QAM) waveform, withwhich envelope tracking coefficients for the peak drain efficiency and the bandwidth of power amplifiers aredetermined. Based on the classical envelope tracking theory, the operation of the supply modulator, which isa key part of the envelope tracking process, is modeled and analyzed mathematically. Then characteristicsof the modulator by setting envelope shaping function as a cubic polynomial and sweeping the coefficients ofthis function was analyzed. By sweeping the coefficients, efficiency and bandwidth at each condition with64-QAM signal was used to obtain optimal point of the supply modulator. Compared to the conventionalshaping functions, the optimized function showed the bandwidth reduction by 12.7 percent point while theefficiency was maintained.
Abstract
In this paper, we suggest a combined cost function to find out the optimal operation of an envelopetracking system, and evaluated its performance with Quadrature Amplitude Modulation (QAM) waveform, withwhich envelope tracking coefficients for the peak drain efficiency and the bandwidth of power amplifiers aredetermined. Based on the classical envelope tracking theory, the operation of the supply modulator, which isa key part of the envelope tracking process, is modeled and analyzed mathematically. Then characteristicsof the modulator by setting envelope shaping function as a cubic polynomial and sweeping the coefficients ofthis function was analyzed. By sweeping the coefficients, efficiency and bandwidth at each condition with64-QAM signal was used to obtain optimal point of the supply modulator. Compared to the conventionalshaping functions, the optimized function showed the bandwidth reduction by 12.7 percent point while theefficiency was maintained.
참고문헌 (10)
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