Approximation of the characteristics for the systems containing variable elements in consideration of minimal realization

The method of approximating the desired variable characteristics by a transfer function containing one kind of variable parameter in terms of minimal realization is described. Two models of the approximating variable transfer function that is minimally realizable are proposed. In the conventional model considering minimal realization, the poles are independent of the variable parameter λ, while in the proposed models, both the poles and zeros depend on λ. Consequently, they can represent a wider range of the variable characteristics. Making use of the property that the approximating transfer function is minimally realizable, the method of improvement of the approximation accuracy for the specified value of λ by use of Markov parameters is also presented