This paper proposes an improved method for describing digital filter structures as part of digital signal processing (DSP) systems, characterized by the high information content of its models. The proposed approach is used to perform the synthesis of graphical analytical models of DSP systems as well as their analysis by means of multilevel decomposition. All the system elements are presented in the form of functional structures, and the input counts processing - by the discrete system - is considered as the process of converting arguments by these functional structures. Moreover, graphical analytical models of basic structures of the finite impulse response (FIR) and infinite impulse response (IIR) filters are developed and integrated with...