%
%   Unit Rect Function
%

function Cr = crect(t,L)
    rise = 0.5*(1 + sign(t+L/2));
    rise(find(rise==0.5))=1;
    
    fall = -0.5*(1 + sign(t-L/2));
    fall(find(fall==-0.5))=-1;
    
    Cr = rise+fall;
end