I am working on a project in which I need to compute the second order difference plot (SODP) of a data series. The data vector is x(n) and I need to compute following values to plot on a graph:
X(n) = x(n+1)- x(n)-----Equation(1)
Y(n) = x(n+2) - x(n-1)-------Equation(2)
Then the plot of X(n) vs. Y(n) will be my SODP. How to compute x(n+1) for first equation and x(n+2) for the second equation in MATLAB. I want to understand x(n+1) is the shifting of x(n) on time scale?