\begin{tikzpicture}[
measure line/.style={thin,|-|},
measure text/.style={midway},
axis line/.style={color=gray,thin,-latex},
axis text/.style={color=gray,},
heading/.style={-stealth},
/pgf/number format/showpos
]
\usetikzlibrary{calc}
\coordinate (base) at (0,0);
\def\numperiod{2}
\def\pulseneut{1}
\def\period{\pulseneut*4}
\def\variance{0.4}
\def\lineexcess{\period*0.1}
\def\height{3}
\def\amp{0.5*\height}
\def\circrad{\amp*0.4}
\def\arrowsep{-\height*0.075}
\def\markerlen{\circrad*0.4}
\newcommand{\pulse}[1]{-- ++(0, \amp) -- ++(#1, 0) -- ++(0, -\amp)}
\newcommand{\mathresult}[1]{%
\pgfmathparse{#1}\pgfmathsetmacro\mymathresult{\pgfmathresult}%
}
\foreach \s in {0,1,2} {
\def\pulsew{\pulseneut+\pulseneut*\variance - \s*\variance}
\def\periodrest{\period-\pulseneut-\pulseneut*\variance+\s*\variance}
\coordinate (curbase) at ($ (base) + (0, \s*\height)$);
\coordinate (start) at ($ (curbase) + (-\lineexcess, 0)$);
\coordinate (end) at ($ (start) + (\period*\numperiod + \period + 2*\lineexcess, 0) $);
\draw[axis line] (start) ++(-0.1*\period, 0) -- (end) node[axis text,anchor=north east]{t};
\draw[axis line] (start) ++(0, -0.1*\amp) -- ++(0, 1.25*\amp) node[axis text,anchor=north east]{V};
\draw[measure line] ($(curbase) + (0, \arrowsep)$) -- ($(curbase) + (\period, \arrowsep)$) node[measure text,below] {20 ms};
\foreach \per in {0,1,...,\numperiod} {
\coordinate (pstart) at ($ (curbase) + (\period*\per, 0) $);
\draw[very thick] (pstart) \pulse{\pulsew} -- ++({\periodrest}, 0);
}
\def\pulsewtxt{\pgfmathparse{2-\s*0.5}\pgfmathresult}
\draw[measure line] (curbase) ++(0,\amp) ++(0, -\arrowsep) -- +(\pulsew, 0) node[measure text,above] {\pulsewtxt\space ms};
};
\def\s{0} % stupid cosine/sine functions don't work as expected :/
\def\rottxt{\pgfmathparse{90-\s*90}\pgfmathprintnumber{\pgfmathresult}°}
\coordinate (circoff) at ($ (base) + (0, \s*\height) + (\period*\numperiod + \period/2, 0) + (\circrad*1.5, \amp*0.6) $);
\draw (circoff) circle(\circrad) node{\rottxt};
\draw[heading] (circoff) ++($(+\circrad, 0)$) -- ++($(+\markerlen, 0)$);
\def\s{1}
\def\rottxt{\pgfmathparse{90-\s*90}\pgfmathprintnumber{\pgfmathresult}°}
\coordinate (circoff) at ($ (base) + (0, \s*\height) + (\period*\numperiod + \period/2, 0) + (\circrad*1.5, \amp*0.6) $);
\draw (circoff) circle(\circrad) node{\rottxt};
\draw[heading] (circoff) ++($(0, +\circrad)$) -- ++($(0, +\markerlen)$);
\def\s{2}
\def\rottxt{\pgfmathparse{90-\s*90}\pgfmathprintnumber{\pgfmathresult}°}
\coordinate (circoff) at ($ (base) + (0, \s*\height) + (\period*\numperiod + \period/2, 0) + (\circrad*1.5, \amp*0.6) $);
\draw (circoff) circle(\circrad) node{\rottxt};
\draw[heading] (circoff) ++($(-\circrad, 0)$) -- ++($(-\markerlen, 0)$);
\end{tikzpicture}