Linear Approximation of Weakly Nonlinear MIMO Systems

A nonlinear multiple-input-multiple-output (MIMO) Volterra system, measured with random multisine signals, can be replaced by an approximating linear MIMO system followed by nonlinear-noise sources. This approximation is a straightforward extension of the approximation to single-input-single-output Volterra systems. For a two-input-two-output cubic system, an optimized measurement strategy is also proposed to reduce as much as possible the influence of nonlinear noise on the measurement of the nonparametric frequency-response function