I've started to learn signal fundamentals and I have to do one exercise and I can't understand something.
It is said that $$x[n]=3\cos(0.1 \Pi n)(u[n+55]-u[n-55]))$$ and that the signal $u[n-m]$ is a unit step with the value $0$ for $n<m$ and $1$ for $n\geq m$
I have made this
MatLab function to plot this signal.
function x = signal(n) % n is passed as n = -100:100;% x = zeros(1,length(n)); for i=1:length(n) if n(i)>-55 && n(i) < 55 x(i) = 3*cos(0.1*pi*n(i)); else x(i) = 0; end end end
Is this OK? I'm having doubt's because I can't understand what $(u[n+55]-u[n-55]))$ means...