• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.91-94
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• 1997

In this paper, pseudo-random ternary sequence (PRTS) was used to investigate the cardiovascular and respiratory responses to hypoxia and hypercapnia. The actual input or this study was the changes in inhaled oxygen and carbon dioxide concentrations. It is hard to randomly change the concentration within a given breath. Since PRTS has almost the same statistical properties as Gaussian white noise, plus it is physically realizable, PRTS is used for this study. Using PRTS and Volterra kernels by Gram-Schmidt orthogonalization procedure, the cardiovascular and respiratory responses to hypoxia and hypercapnia were analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1254-1264
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• 2008

This paper suggests an extended memory polynomial model that improves accuracy in modeling memory effects of RF power amplifiers(PAs), and verifies effectiveness of the suggested method. The extended memory polynomial model includes cross-terms that are products of input terms that have different delay values to improve the limited accuracy of basic memory polynomial model that includes the diagonal terms of Volterra kernels. The complexity of the memoryless model, memory polynomial model, and the suggested model are compared. The extended memory polynomial model is represented with a matrix equation, and the Volterra kernels are extracted using least square method. In addition, the structure of digital predistorter and digital signal processing(DSP) algorithm based on the suggested model and indirect learning method are proposed to implement a digital predistortion linearization. To verify the suggested model, the predicted output of the model is compared with the measured output for a 10W GaN HEMT RF PA and 30 W LDMOS RF PA using 2.3 GHz WiBro input signal, and adjacent-channel power ratio(ACPR) performance with the proposed digital predistortion is measured. The proposed model increases model accuracy for the PAs, and improves the linearization performance by reducing ACPR.