\def\layersep{1.5cm}
\def\outsep{0.7cm}
\def\dy{1.25}

\begin{tikzpicture}[draw=black!50, node distance=\layersep, font=\sffamily]
    \tikzstyle{node}=[circle,fill=black,minimum size=2pt,inner sep=0pt]
    \tikzstyle{block}=[draw=black,rectangle,fill=none,minimum width=3cm, minimum height=2cm, inner sep=0pt]
    \tikzstyle{annot} = []

	\node[node] (xc) at (0, -\dy cm) {};
    \node[block, text width = 3cm, align= center] (DSP) at (2*\layersep, -\dy cm) {LTI System \\ $h[n]\leftrightarrow H(e^{j\omega})$};
	\coordinate (yc) at (4*\layersep, -\dy cm) {};
		
    \path[->, >=stealth, shorten >= 0pt] (xc) edge (DSP);
    \path[->, >=stealth, shorten >= 0pt] (DSP) edge (yc);
    
	\node[block, draw=none] (tx_signal) at ($(xc.center)+(-1, 0.75)$) {\resizebox{7cm}{!}{\input{figs/random_sequence.tex}}};
    \node[below = 0.5mm of xc] {$x[n]$};	
	\node[block, draw=none] (tx_signal) at ($(yc.center)+(2.5, 0.75)$) {\resizebox{7cm}{!}{\input{figs/random_sequence.tex}}};
    \node[below = 0.5mm of yc] {$y[n]$};
\end{tikzpicture}