The invention relates to a method for analyzing substances during which a substance is subjected to an excitation and a corresponding response is observed. The evaluation ensues in such a manner that a parametric model for the correlation between the excitation and the response is predetermined. The model parameters are determined from values of the excitation and from observed values of the response in the time domain. The transfer function is calculated therefrom in the frequency range, and characteristic quantities of the substance are directly calculated from the transfer function.
