documentclass[a4paper,12pt]{article}
usepackage{pgfplots,filecontents}

begin{filecontents*}{data.csv}
"Amplitude","notes: data set 1",
X,Y,
1,1,
2,2,
3,3,
4,4,

"CH1","notes: data set 1",
end{filecontents*}

begin{document}
    begin{tikzpicture}
        begin{axis}
        addplot gnuplot [raw gnuplot, mark=none, black]{
            set datafile separator comma;
            plot "data.csv" using 1:2 every ::2::5 with lines;
        };
        end{axis}
    end{tikzpicture}
end{document}

documentclass[a4paper,12pt]{article}
usepackage{pgfplots,filecontents}

begin{filecontents*}{data.csv}
"Amplitude","notes: data set 1",
X,Y,
1,1,
2,2,
3,3,
4,4,

"Amplitude","notes: data set 2",
X,Y,
1,7,
2,6,
3,5,
4,4,
5,3,
6,2,
7,1,

"CH1","notes: data set 1",
"CH1","notes: data set 2",
end{filecontents*}

begin{document}
    begin{tikzpicture}
        begin{axis} [width=0.5textwidth,height=7cm,
        ]
        addplot gnuplot [raw gnuplot, mark=none, black]{
            set datafile separator comma;
            plot "data.csv" using 1:2 every ::2::5 with lines;
        };
        end{axis}
    end{tikzpicture}
end{document}