
\begin{tikzpicture}
[+preamble]
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
[/preamble]
\begin{axis}[
ticks=none,
xmin=-1*pi,
xmax=5*pi,
ymin=-1.5,
ymax=1.5,
axis lines=middle,
xlabel=$t$,
ylabel=$y$,
disabledatascaling]
\addplot[solid,samples=200,domain=-0.5*pi:4.5*pi] {sin(deg(x))};
\addplot[solid,samples=200,domain=-0.5*pi:4.5*pi] {sin(deg(x+2))};
\draw [<->](1,{sin(deg(3))})--(3,{sin(deg(3))})node[above left,position=0.1]{$\theta$};
\end{axis}
\end{tikzpicture}