A comparison of the Volterra series-based nonlinear S-parameters and X-parameters

In this contribution, two different approaches to the analysis of nonlinear analog circuits in the frequency domain using scattering variables are examined, the nonlinear scattering parameters (S-parameters) based on the Volterra series and the X-parameters. After the theoretical backgrounds are shortly recapitulated, the benefits and drawbacks of each method are outlined. Both methods are applied to an exemplary weak nonlinear circuit and the obtained results are compared. As a result, it is concluded that the X-parameter approach can be expanded in order to increase the accuracy of the approach in dependency of the small signal.