\begin{texdraw}
\drawdim cm

% abcisas
\move(-2.5 0)
\avec(3 0)
\rmove(0 -0.2)
\textref h:C v:T \htext{$t$}

% ordenadas
\move(0 -1.5)
\avec(0 2.6)
\rmove(-0.2 0)
\textref h:R v:C \htext{$f(t)$}

%t0
\move (1 -1)
\lpatt(0.1)
\lvec (1 2)
\lpatt()
\move(1.1 -0.1)
\textref h:L v:T \htext{$t_0$}


% escalones
\linewd 0.06

%u(t)
\move(0 1)
\lvec(2.5 1)
\move(0.2 1.1)
\textref h:L v:B \htext{$u(t)$}

%2u(t-t0)
\move(1 2)
\lvec(2.5 2)
\move(1.1 2.1)
\textref h:L v:B \htext{$2u(t-t_0)$}

%-u(t0-t)
\move(1 -1)
\lvec(-2.5 -1)
\move(-0.1 -0.9)
\textref h:R v:B \htext{$-u(t_0-t)$}




\end{texdraw}