I have a displacement signal and I have to get the acceleration from it. I used several method to get the displacement, but all of them fail somehow. Here you can see the signal: http://imageshack.us/f/89/signalgn.jpg/
I used: 1- the formula: diff(disp,2)./(run(i).t(2)).^2; The signal magnitude is too high 2- the spectral differentiation through the derivation property of Fourier transform. Here again, I get high signal magnitude. Method 1 matches with method 2 3- I used the simulink derivation block. The signal looks reasonable.
Why is there this difference beeween methods 1 and 2 with method 3. How could I implement method 3 through a script, without creating a simulink model?