A trade-off analysis on the number of scrolls and the operating frequency is presented. To do so, nonlinear system parameters, real physical active device parameters and the operating frequency are taken into account to model the behavior of the saturated nonlinear function series approximated by a piecewise-linear description. As a consequence, not only the trade-off between the number of scrolls and the operating frequency is investigated, which depends directly on the behavior at the operating frequency of the nonlinear function, but also chaotic attractors are efficiently synthesized without the application of scaling techniques. Theoretical calculations are in good agreement with numerical simulations and a prediction on the maximum number of scrolls that can be synthesized for a particular frequency is also given.

A novel extended method to approximate the behavioral model of current-mode analog circuits (CMACs) is presented. The nullor is employed to model the behavior of a MOS transistor (MOST) together with its parasitic elements. In a first part, the signal-path (SP) into a CMAC is approached by using the nullor properties. In the second part, the behavioral model associated to each MOST is generated and it is more simple in comparison with the original model. As a consequence, in the third part, an admittance matrix of reduced size is built and used to compute small-signal characteristics of CMACs, where the order is given by the number of SP-nodes minus the number of nullors. The proposed technique is illustrated by computing the fully-symbolic transfer function of a positive second generation current conveyor (CCII+) and compared with Hspice simulation.