 A discrete signal, on the other hand, can be modeled as a function defined only on a set of points, such as the set of integers.A discrete signal of formula_1-dimensions can be represented in the spatial domain as formula_7.A mixed signal is a multidimensional signal that is modeled as a function of some continuous variables and some discrete ones, for example an ensemble of time waveforms recorded from an array of electrical transducers is a mixed signal.The ensemble can be modeled with one continuous variable, time, and one or more discrete variables to index the transducers.