Patent ID: 8078446

Claim:
A linear time-invariant system modeling apparatus, comprising: a processing resource arranged to receive, when in use, model data constituting to a model of a linear time-invariant system, the model data including residual value data and scattering data, wherein the processing resource is arranged to perform, when in use, a singular value decomposition in respect of the scattering data, the scattering data corresponding, when expressed in matrix form, to a scattering matrix in a state-space representation of the model; and the processing resource is also arranged to use, when in use, a result of the singular value decomposition in order to generate residual value modification data for a non-passive interval of a predetermined frequency range of a linear time-invariant system, and apply the residual value modification data to the residual value data, the residual value data corresponding, when expressed in the matrix form, to a residual value matrix in the state-space representation of the model.