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Intermodulation Distortion (intermodulation + distortion)
Selected AbstractsApplication of the envelope-transient method to the analysis and design of autonomous circuitsINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 6 2005Almudena Suárez Abstract The envelope transient enables a very efficient simulation of circuits with two different time scales, such as those that contain modulated signals (for example, amplifier or mixers), where an accurate prediction of intermodulation distortion is needed. The method has also been extended to oscillator analysis, where it requires additional techniques in order to avoid convergence to degenerate mathematical solutions, for which the circuit is not actually oscillating. It allows an efficient analysis of transients in these circuits and an accurate prediction of the phase-noise spectrum. This article presents an overview of the envelope-transient method and its most recent applications to the simulation of autonomous circuits, such as free and forced oscillators, frequency dividers, and phase-locked loops. Using this method, the operation bands of these circuits (which are delimited by qualitative stability changes or bifurcations) can be determined in a straightforward manner. This technique can also be applied to predict intermodulation distortion in self-oscillating mixers and to simulate the response of synchronized oscillators containing modulated signals. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source] Modeling power and intermodulation behavior of microwave transistors with unified small-signal/large-signal neural network modelsINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2003F. Giannini Abstract This article presents a detailed procedure to learn a nonlinear model and its derivatives to as many orders as desired with multilayer perceptron (MLP) neural networks. A modular neural network modeling a nonlinear function and its derivatives is introduced. The method has been used for the extraction of the large-signal model of a power MESFET device, modeling the nonlinear relationship of drain-source current Ids as well as gate and drain charge Qg and Qd with respect to intrinsic voltages Vgs and Vds over the whole operational bias region. The neural models have been implemented into a user-defined nonlinear model of a commercial microwave simulator to predict output power performance as well as intermodulation distortion. The accuracy of the device model is verified by harmonic load-pull measurements. This neural network approach has demonstrated to predict nonlinear behavior with enough accuracy even if based only on first-order derivative information. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 276,284, 2003. [source] Behavioral modeling of GaN-based power amplifiers: Impact of electrothermal feedback on the model accuracy and identificationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009Roberto Quaglia Abstract In this article, we discuss the accuracy of behavioral models in simulating the intermodulation distortion (IMD) of microwave GaN-based high-power amplifiers in the presence of strong electrothermal (ET) feedback. Exploiting an accurate self-consistent ET model derived from measurements and thermal finite-element method simulations, we show that behavioral models are able to yield accurate results, provided that the model identification is carried out with signals with wide bandwidth and large dynamics. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2789,2792, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24732 [source] Analog characteristics of electroabsorption modulator for RF/optic conversion; RF gain and IMD3MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2006Yong-Duck Chung Abstract We design and fabricate a traveling-wave electroabsorption modulator for RF/optic conversion. The RF gain is measured with a simple RF/optic link. It is related to the optical transfer curve. The input optical power causes the change of the transfer curve so that the RF gain varies accordingly. The RF/optic conversion gain shows a close relationship with the slope efficiency of transfer curve. Linearity is also one of the important characteristics for analog applications. We evaluate the linearity of the module from the 3rd -order intermodulation distortion (IMD3). © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1151,1155, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21564 [source] | ||||||||||