Исходники иллюстрации

\documentclass[tikz]{standalone}\input{pre.tex}\begin{document}\begin{tikzpicture}
    \xdef\darkness{0}
    \xdef\opa{0.2}

    \xdef\SIZE{6}
    \xdef\setka{0}

    \input{setka}

    \draw[
        domain=0:5*pi,
        smooth,thick,
        variable=\x,
        samples=100,
        black, 
        dashed,
    ] plot ({\x/pi},{sin(\x r)/2}); 

    % \draw[
    %     domain=0:5*pi,
    %     smooth,thick,
    %     variable=\x,
    %     samples=100,
    %     magenta, 
    %     % yshift=3cm
    % ] plot ({\x/pi},{sin((\x) r)}); 

    \draw[
        domain=pi:5*pi,
        smooth,thick,
        variable=\x,
        samples=100,
        black, 
        dashed,
        % yshift=3cm
    ] plot ({\x/pi},{-sin((\x) r)/2});  

    \draw[magenta,very thick] (1,0)-- (5,0);   

    \begin{scope}[xshift=0cm, yshift=0.5cm]
        \lineann[0.5]{0}{1}{сдвиг\\ фазы}{white}
    \end{scope}        

\end{tikzpicture}\end{document}