The Experts below are selected from a list of 6657 Experts worldwide ranked by ideXlab platform
Young Ho Jung - One of the best experts on this subject based on the ideXlab platform.
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Adaptive digital predistortion for the power amplifiers based on look-up table with tanh as a nonlinear Indexing Function
2008 Asia-Pacific Microwave Conference, 2008Co-Authors: Tak Su Moon, Choon Sik Cho, Lee Jong Hyeuk, Young Ho JungAbstract:This paper presents performance results of DPD using the nonlinear Indexing Function based on tanh. Three DPDs characterized by different Indexing Functions use the same estimation algorithm. However, among these methods, the tanh Indexing method provides the best performance for linearization. Under the condition of 0 dB input back-off, the proposed Indexing scheme performs more linearization and faster estimation compared with others. Apoint to be more important is that it can be achieved by realizing a better index Function for further optimizing the performance of power amplifiers.
Choon Sik Cho - One of the best experts on this subject based on the ideXlab platform.
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linearity enhancement of rf power amplifier using digital predistortion with tanh as a nonlinear Indexing Function
The Journal of Korean Institute of Electromagnetic Engineering and Science, 2011Co-Authors: Yeonjung Seong, Choon Sik Cho, Jaewook LeeAbstract:In this paper, we design a digital predistortion(DPD) for linearity enhancement of RF power amplifier operating in 900 MHz band. We verify improvement of linearity by comparing the proposed DPD using tanh as a nonlinear Indexing Function and the DPD using linear Indexing Function based on signal amplitude. The digital predistortion is realized by look-up table(LUT) method, and the Saleh model is employed for power amplifier modeling, then a commercial power amplifier module is used for measurement. The LUT has 256 tables, and the NLMS(Normalized Least Mean Square) algorithm was utilized for an adaptive algorithm for estimation. As a result, we improve the ACLR(Adjacent Channel Leakage Ratio) by around 15 dB.
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Adaptive digital predistortion for the power amplifiers based on look-up table with tanh as a nonlinear Indexing Function
2008 Asia-Pacific Microwave Conference, 2008Co-Authors: Tak Su Moon, Choon Sik Cho, Lee Jong Hyeuk, Young Ho JungAbstract:This paper presents performance results of DPD using the nonlinear Indexing Function based on tanh. Three DPDs characterized by different Indexing Functions use the same estimation algorithm. However, among these methods, the tanh Indexing method provides the best performance for linearization. Under the condition of 0 dB input back-off, the proposed Indexing scheme performs more linearization and faster estimation compared with others. Apoint to be more important is that it can be achieved by realizing a better index Function for further optimizing the performance of power amplifiers.
Jaewook Lee - One of the best experts on this subject based on the ideXlab platform.
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linearity enhancement of rf power amplifier using digital predistortion with tanh as a nonlinear Indexing Function
The Journal of Korean Institute of Electromagnetic Engineering and Science, 2011Co-Authors: Yeonjung Seong, Choon Sik Cho, Jaewook LeeAbstract:In this paper, we design a digital predistortion(DPD) for linearity enhancement of RF power amplifier operating in 900 MHz band. We verify improvement of linearity by comparing the proposed DPD using tanh as a nonlinear Indexing Function and the DPD using linear Indexing Function based on signal amplitude. The digital predistortion is realized by look-up table(LUT) method, and the Saleh model is employed for power amplifier modeling, then a commercial power amplifier module is used for measurement. The LUT has 256 tables, and the NLMS(Normalized Least Mean Square) algorithm was utilized for an adaptive algorithm for estimation. As a result, we improve the ACLR(Adjacent Channel Leakage Ratio) by around 15 dB.
Fadhel M Ghannouchi - One of the best experts on this subject based on the ideXlab platform.
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adaptive digital rf predistortion using a nonuniform lut Indexing Function with built in dependence on the amplifier nonlinearity
International Microwave Symposium, 2004Co-Authors: Slim Boumaiza, Jing Li, M Jaidanesaidane, Fadhel M GhannouchiAbstract:This paper reports on an integrated adaptive digital/RF predistorter using a nonuniform spaced lookup table (LUT) and in-phase/quadrature (I/Q) RF vector multiplier (VM). The LUT contents are directly deduced from the baseband input and output signals of the power amplifier (PA). In addition, a new nonlinear Indexing Function of the predistortion LUT with built-in dependence on the PA nonlinearity is proposed. This Function is made to be robust to the input signal statistics. A comparison of this new indexation method with conventional approaches, namely, power and logarithmic power indexation Functions, is carried out. The superiority of the proposed scheme is demonstrated in particular for class-AB amplifiers where the gain of the PA varies over the whole input range of the drive signal. The measured output spectrum of a linearized 90-W peak lateral double-diffused metal-oxide-semiconductor PA reveals a significant reduction of the power emission at the adjacent channels of approximately 15 dB under IS95, single-carrier, and multicarrier wide-band code-division multiple-access signals. The experimental evaluation is carried out using an RF/digital predistorter prototype that mainly includes an envelope detector, a linear I/Q RF VM, field-programmable gate array and digital signal processor, and fast analog/digital and digital/analog converters.
Tak Su Moon - One of the best experts on this subject based on the ideXlab platform.
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Adaptive digital predistortion for the power amplifiers based on look-up table with tanh as a nonlinear Indexing Function
2008 Asia-Pacific Microwave Conference, 2008Co-Authors: Tak Su Moon, Choon Sik Cho, Lee Jong Hyeuk, Young Ho JungAbstract:This paper presents performance results of DPD using the nonlinear Indexing Function based on tanh. Three DPDs characterized by different Indexing Functions use the same estimation algorithm. However, among these methods, the tanh Indexing method provides the best performance for linearization. Under the condition of 0 dB input back-off, the proposed Indexing scheme performs more linearization and faster estimation compared with others. Apoint to be more important is that it can be achieved by realizing a better index Function for further optimizing the performance of power amplifiers.
