# convolution expression h(n,k) = h(n-k)

As a new to DSP concepts want to understand the meaning of impulse response and why we do $$h(n-k)$$ in convolution and $$h(n+k)$$ in correlation.

• The direction in convolution does not matter, it can go either way. Convert convolution numerically into system of linear equations and everything becomes clear. Jan 10 '20 at 16:47