\documentclass[12pt,a3paper,ngerman,landscape]{article}

\usepackage{enumerate}
\usepackage[german]{babel}
\usepackage[T1]{fontenc}
\usepackage[european]{circuitikz}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{caption2}
\usepackage{subfigure}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{fancyhdr}
\usepackage{geometry}
\usepackage{bibgerm}
\usepackage{makecell}
\usepackage{lastpage}
\usepackage{multirow}
\usepackage{xcolor}
\usepackage{url}
\usepackage{esint}
\usepackage{pdfpages}
\usepackage{pgfplots}
\pgfplotsset{compat=newest} % Allows to place the legend below plot
\usepgfplotslibrary{units} % Allows to enter the units nicely
\usetikzlibrary{shapes.geometric}

\usetikzlibrary{arrows.meta}
\usetikzlibrary{matrix}
\usetikzlibrary{calc}
\usetikzlibrary{decorations.pathreplacing}
\usetikzlibrary{patterns}
\usetikzlibrary{positioning}
\usetikzlibrary{arrows, decorations.markings}

\graphicspath{{./fig/}{./}} % Suchpfad für Bilder

\begin{document}
\pagestyle{empty}
\begin{figure}[!h]
    \centering
    \begin{tikzpicture}[square/.style={regular polygon,regular polygon sides=4}]

    \node[inner sep=0pt,label=below:Mic] (mic) at (-5,0) {\includegraphics[width=.05\textwidth]{example-image-a}};
    \matrix[label=below:FFT Filterbank] (fftFilter) [draw]  at (5,0) {
    \node {\includegraphics[width=.25\linewidth]{example-image-a}}; \\
    \draw [Circle-{Circle[open]}, thick] (0,0) -- (0,0.75); \\
    \node {\includegraphics[width=.25\linewidth]{example-image-a}}; \\
    };

    \node[inner sep=0,minimum size = 0,right of=fftFilter, xshift = 4cm] (midPoint) {};

    \node[inner sep=0pt,above=of fftFilter,xshift = 10cm,yshift = 3cm,label=below:Frequenz Band 1] (band1) {\includegraphics[width=.2\textwidth]{example-image-a}};
    \node[inner sep=0pt,below=of band1,label=below:Frequenz Band 2] (band2) {\includegraphics[width=.2\textwidth]{example-image-a}};
    \node[inner sep=0pt,below=of band2,label=below:Frequenz Band 3] (band3) {\includegraphics[width=.2\textwidth]{example-image-a}};
    \node[inner sep=0pt,below=of fftFilter,xshift = 10cm,label=below:Frequenz Band M] (bandN) {\includegraphics[width=.2\textwidth]{example-image-a}};

    \path (band3) -- (bandN) node [black, font=\Huge, midway, sloped, xshift=3mm] {$\dots$};

    \draw[very thick] (fftFilter) to (midPoint) ;
    \draw[very thick, ->] (midPoint) |- (band1) ;
    \draw[very thick, ->] (midPoint) |- (band2) ;
    \draw[very thick, ->] (midPoint) |- (band3) ;
    \draw[very thick, ->] (midPoint) |- (bandN) ;

    \node [rectangle,draw,text width=1.5cm,minimum height=1.5cm,name = ADC,right of=mic,xshift = 3cm,label=below:AD-Wandler] {};
    \draw (ADC.south west) -- (ADC.north east);
    \node[yshift=1cm,xshift = 6mm] at (ADC.south west) {A};
    \node[yshift=5mm,xshift = -6mm] at (ADC.south east) {D};
    \draw[very thick,->] (mic) -- (ADC);
    \draw[very thick,->] (ADC) to (fftFilter);

    \node[right of=band1,xshift = 4cm,label=below:Energie, rectangle,text width=1.5cm,minimum height=1.5cm, draw, align=center] (sum1) {$\sum$};
    \node[right of=band2,xshift = 4cm,label=below:Energie, rectangle,text width=1.5cm, minimum height=1.5cm,draw, align=center] (sum2) {$\sum$};
    \node[right of=band3,xshift = 4cm,label=below:Energie, rectangle,text width=1.5cm,minimum height=1.5cm, draw, align=center] (sum3) {$\sum$};
    \node[right of=bandN,xshift = 4cm,label=below:Energie, rectangle,text width=1.5cm,minimum height=1.5cm, draw, align=center] (sumN) {$\sum$};

    \draw[very thick, ->] (band1) to (sum1);
    \draw[very thick, ->] (band2) to (sum2);
    \draw[very thick, ->] (band3) to (sum3);
    \draw[very thick, ->] (bandN) to (sumN);

    \node[inner sep=0,minimum size = 0,right of=fftFilter, xshift = 17cm] (midPoint2) {};
    \draw[very thick] (sum1) -| (midPoint2) (sum2) -| (midPoint2) (sum3) -| (midPoint2) (sumN) -| (midPoint2);
    \node[right of=midPoint2, xshift = 2cm, label=below:1. Selektion,text width=1.5cm,minimum height=1.5cm, draw, align=center] (sel1) {SEL};
    \draw[very thick,->] (midPoint2) to node [above] {M} (sel1);
    \node[right of=sel1,xshift = 3cm, label=below:2. Selektion,text width=1.5cm,minimum height=1.5cm, draw, align=center] (sel2) {SEL};
    \end{tikzpicture}
\end{figure}
\end{document}