Translations:Convolution - book/5/en

What is convolution? Let us consider the action of the Nth-order causal FIR filter on an input given by the equally spaced sampled values $x_{0},x_{1},x_{2},...,x_{M}$. The numbers $x_{n}$ are going into the filter; that is, the input is as follows: $x_{-1}$ enters at time $n=-1,x_{0}$ enters at time $n=0,x_{1}$ enters at time $n=1,x_{2}$ enters at time n = 2, and so forth.