PHYSICAL AND BEHAVIORAL CIRCUIT MODELING OF THE SP-12 SAMPLER

Aliasing, usually considered an artifact of discrete time systems to be avoided, is found to be an aesthetic feature of the E-MU SP-12 sampler/drum machine. This paper presents the steps in modeling the SP-12 as a signal processing system. Measurements of the characteristics of the SP-12 are presented. The signal path is analyzed to produce a physically based model of the circuit. Circuit analysis in SPICE provides transfer functions, which are converted into digital filters by system identification. Aliasing is implemented using interpolation and downsampling. The results of the algorithm are compared to samples from the original system.