A first approach to the distortion analysis of nonlinear analog circuits utilizing X-parameters

[摘要] In this contribution a first approach to the distortion analysis of nonlinear2-port-networks with X-parameters¹ is presented. The X-parameters introducedby Verspecht and Root (2006) offer the possibility to describe nonlinearmicrowave 2-port-networks under large signal conditions. On the basis ofX-parameter measurements with a nonlinear network analyzer (NVNA) behavioralmodels can be extracted for the networks. These models can be used toconsider the nonlinear behavior during the design process of microwavecircuits. The idea of the present work is to extract the behavioral models inorder to describe the influence of interfering signals on the output behaviorof the nonlinear circuits. Hereby, a simulator is used instead of a NVNA toextract the X-parameters. Assuming that the interfering signals arerelatively small compared to the nominal input signal, the output signal canbe described as a superposition of the effects of each input signal. In orderto determine the functional correlation between the scattering variables, apolynomial dependency is assumed. The required datasets for the approximationof the describing functions are simulated by a directional coupler model inCadence Design Framework. The polynomial coefficients are obtained by aleast-square method. The resulting describing functions can be used topredict the system's behavior under certain conditions as well as the effectsof the interfering signal on the output signal.

¹ X-parameter is a registered trademark of Agilent Technologies, Inc.

[学科分类] 电子、光学、磁材料