beta=.05
T=25
w=(2*pi)/T;
a(2502:end)=[ ];
uddg=a;
u=[ ];
for t=0:.02:50
    f=[ ];
    for tau=0:.1:t
        uddgtau=interp1([0:.02:50],uddg,tau);
        f1=uddgtau.*exp(-(beta*w*(t-tau))).*sin(w*(t-tau));
        f=[f f1];
    end
    c=4-2*rem(1:length(f),2);
    c(1)=1;
    c(end)=1;
    s=sum(c.*f)*.01/3/w;
    u=[u s];
end
plot([0:.02:50],u)
sdmax=max(abs(u))