Parametric MIMO parallel Wiener identification

Abstract

This paper proposes a parametric identification method for multi-input multi-output parallel Wiener systems. The linear dynamic parts of the system are modeled by a parametric rational function in the continuous or discrete time variable, while the static nonlinearities are represented by a linear combination of nonlinear basis functions. The identification method uses a three step procedure to obtain initial estimates. In the first step, the frequency response matrix of the best linear approximation is estimated for different input excitation levels. In the second step, the power dependent dynamics are decomposed over a number of parallel orthogonal branches. In the last step, the static nonlinearities are estimated using a linear least squares estimation. Finally both linear and nonlinear parameters are estimated together using a nonlinear optimization procedure. The method is illustrated on a simulation example.