uweziegenhagen.de

\begin{tikzpicture}
%\draw[step=0.5cm,lightgray,thin] (0,0) grid (10,7);
\draw[very thick, black,->](1,1) -- (9.5,1);
\draw[very thick, black,->](1,1) -- (1,6.5);
\draw[very thick, green,](3,1) -- (3,6);
\draw[very thick, orange,](5,1) -- (5,6);
\draw[very thick, black](7,1) -- (7,6);
\draw[very thick, magenta](9,1) -- (9,6);
 
\draw[very thick, gray,](1,1) -- (3,5.5) -- (5,4) -- (7,4)--(9,1);
% max amp line
\draw[thick, gray,dotted](0.8,5.5) -- (9.5,5.5);
 
\draw[very thick, blue,->](6,1.1) -- (6,3.9);
 
\draw[very thick, green,->](1.1,5.65) -- (2.9,5.65);
\draw[very thick, orange,->](3.1,5.65) -- (4.9,5.65);
 
\draw[very thick, blue](5.1,4) -- (6.9,4);
 
\draw[very thick, magenta,->](7.1,5.65) -- (8.9,5.65);
 
\node[label=left:0] (A) at (1,1) {};
\node[label=below:t] (B) at (9.5,1) {};
\node[label=left:{{\scriptsize Amp\textsubscript{max}}}] (C) at (1,5.5) {};
 
\node[label=above:A] (D) at (2,5.5) {};
\node[label=above:D] (E) at (4,5.5) {};
\node[label=left:S] (F) at (6,2.5) {};
\node[label=above:R] (G) at (8,5.5) {};
 
\draw[very thick, black,->](1,0.5) -- (1,0.9);
\draw[very thick, black,->](7,0.5) -- (7,0.9);
 
\node[label=above:{Key press}] (D) at (1.1,-0.2) {};
\node[label=above:{Key release}] (D) at (7.2,-0.2) {};
 
\end{tikzpicture}