Accurate Discretization of Analog Audio Filters With Application to Parametric Equalizer Design

This paper is concerned with accurate discretization of linear analog filters such that the frequency response of the discrete time filter accurately matches that of the continuous time filter. The approach is based on formal reconstruction of the continuous time signal using Shannon´s interpolation theorem and numerical solving of the differential equation corresponding to the analog filter. When the formal continuous time system is sampled, the resulting filter reduces to discrete linear filter, which can be realized either as a state space model or as an infinite impulse response (IIR) filter. The proposed methodology is applied to design of filters for parametric equalizers.