Weakly Nonlinear Time-Varying Systems

The theory of linear time-varying systems can be extended to weakly-nonlinear time-varying (WNTV) systems in a similar way as we did for linear time-invariant systems. In this chapter we first define WNTV systems mathematically and highlight some important differences from the theory of WNTI systems. We then discuss weakly-nonlinear periodically time-varying (WNPTV) systems. These type of systems generate a characteristic spectrum that is relatively easy to describe and is relevant, for example, in the study and design of communication systems.