The present paper considers a constant-parameter estimation al~orithm for an analog transfer function by discrete observations fof the object's input and output variables. The algo rithm is bas~d on supplementary variables and least-squares meth ods. It. is assumed, that the order of (,he transfer fUllction is known and the derh~tive~ of the input and output variables are nOI1- measurable. The supplementary variables and their derivatives are constructed from dicrete observations of the input and output vari ables by applying a numerically realized analog filter. Investigation results for the estimate properties are presented. The results were obtained by the method of statistical sim ulation. •