Bran, To make the question clear, you have to describe the nature( dimensions) of the acquired signal, and the sampling frequency. However let us make this simple simulation : dropping a simple object and storing the signal for 2 seconds, with sampling frequency Fs=1000Hz :
t=0:1e-3:2-1e-3;
a=0.5*9.81*t.^2; % the stored signal which is naturally the acceleration due to gravity .
You integrate this quantity :
v=integral(a,1e-2); % with 1e-2 as step .
figure, plot(t,a,t,v,'r'), legend(' Acceleration','Velocity');
