1. The problem statement, all variables and given/known data http://img166.imageshack.us/img166/1162/untitledte2.jpg [Broken] 2. Relevant equations Convolution y[n] = x[n] * h[n] 3. The attempt at a solution I've never done convolutions going backwards.. right off the bat, I know I'll noly have 2 terms in the convolution sum, because of x term, but I don't have a clue how to determine the h[n]. It is not possible to write a response y as a convolution between x and h because h is unknown. Any ideas?