Frequency domain theory of nonlinear Volterra systems based on parametric characteristic analysis.

The frequency domain methods tor linear systems are well accepted by engineers and have been widely applied in engineering practice because the transfer function of linear systems can always provide a coordinate-free and equivalent description for system characteristics and are convenient to be used for the system analysis and design. Although the analysis and design of linear systems in the frequency domain have been well established and the frequency domain methods for nonlinear systems have aheady been investigated for many years, the frequency domain analysis for nonlinear systems is far from being fully developed.