Linearization of large-signal scattering functions

We describe a linearization of large-signal scattering functions describing weakly nonlinear device behavior. The linearization takes on a convenient form similar to scattering parameters that clearly illustrates the role of phase-conjugated mixing products in the theory. We develop rules for the evolution of the linearization with time. We illustrate the theory with transistor measurements and apply the theory to the characterization of the reflection coefficients of a microwave source in its large-signal operating state.