DiscreteConvolve

DiscreteConvolve[f, g, n, m] gives the convolution with respect to n of the expressions f and g.

DiscreteConvolve[f, g, {n1, n2, ...}, {m1, m2, ...}] gives the multidimensional convolution.

Examples

Convolve two sequences:

DiscreteConvolve[UnitStep[n], UnitStep[n], n, m]

Please visit the official Wolfram Language Reference for more details.