Volterra systems with more than one input port — distortion in a frequency converter

Consider a nonlinear system, with memory, which has two input ports and one output port. It is assumed that the system can be represented by a double Volterra series. Two results for such a system are stated in Part I. The first is a general expression for the sinusoidal components of the output y (t) when the two inputs x u (t) and x v (t) are sums of sinusoidal terms. The second result is an expression for the power spectrum of y (t) when x u (t) is a stationary Gaussian process and x v (t) = P cos pt. Part II is concerned with using results from the theory of Volterra series for multi-input systems to calculate the third-order distortion in an idealized frequency converter.