\begin{tikzpicture}[->, >=stealth, shorten >= 0pt, draw=black!50, node distance=3cm, font=\sffamily]
		\tikzstyle{node}=[circle,fill=black,minimum size=2pt,inner sep=0pt]
		\tikzstyle{block}=[draw=black,rectangle,fill=none,minimum size=1.5cm, inner sep=0pt]
		
		\node[node] (xc) {};
		\node[block, right=1cm of xc, text width = 1cm, align= center] (AA) {$H(z)$};
		\node[block, right of=AA, text width = 1cm, align= center] (DSP) {$~~M$};
		\draw[-latex, shorten >= 15pt, shorten <= 15pt, line width=0.75pt] ($(DSP.north)-(5pt, 0)$) -- ($(DSP.south)-(5pt, 0)$) {};
		\coordinate (yc) at ($(DSP.east)+(1cm, 0)$) {};
		
		\coordinate (mid) at ($(AA.east)!0.5!(DSP.west)$) {};
			
		
		\path (xc) edge (AA);
		\path (AA) edge (DSP);
		\path (DSP) edge (yc);
		
		\node[above = 0mm of mid, text width = 1cm, align=center] {$\tilde{x}[n]$};
		\node[above = 0mm of xc, text width = 1cm, align=center] {$x[n]$};
		\node[above = 0mm of yc, text width = 1cm, align=center] {$y[n]$};
\end{tikzpicture}