\documentclass[convert, transparent]{standalone}
\usepackage[utf8]{inputenc}
\usepackage{circuitikz}
\usepgflibrary{arrows.meta} % Uso de biblioteca de flechas
\usetikzlibrary{snakes, shapes} % Biblioteca de "serpientes" y formas
% Definición de estilos
\tikzstyle{block} = [draw,very thick, rectangle,minimum height=6cm, minimum width=4cm]
\tikzstyle{ann} = [font=\Large \bf ,inner sep=1pt, align=center] % Estilo de nodo
\tikzstyle{arr} = [very thick,-Stealth] % Estilo de flecha
\begin{document}
\begin{tikzpicture}
% Diagrama de un Modulador con codificación reticulada (TCM)
	% Bloque codificador
	\node[ann,align=center] at (4,4){Código\\ de retícula};
	\node[ann,align=center] at(-1,0){$k$ \\ $bits$};
	\draw[black, thick, snake=brace] (-0.25,-2.5) -- (-0.25,2.5); % Llave de k-bits
	\draw[very thick,-Stealth] (0,1)--(2,1);
	\draw[very thick,-Stealth] (0,2)--(2,2);
	\foreach \s in {0.5, 0,...,-1.5}
	\node at (1,\s){$\cdot$};
	\draw[very thick,-Stealth] (0,-2)--(2,-2);
	\node[block,ann] at(4,0)(codi){Codificador \\Convolucional};
	% Conexiones entre bloques
	\draw[very thick,-Stealth] (6,1)--(8,1);
	\draw[very thick,-Stealth] (6,2)--(8,2);
	\draw[very thick,dashed,-Stealth] (6,-2)--(8,-2); % Conexión ''punteada''
	\node [ann,align=center] at(7,0){$k+1$ \\$bits$};
	% Bloque Modulador
	\node[ann,align=center] at (10,4){Asignador \\ de constelación};
	\node[block,ann] at(10,0)(cons){M-ASK\\o M-PSK  \\o M-QAM \\ \\$M=2^{k+1}$};
	\draw[arr] (cons)--(14,0) node[ann, right=10,align=left]{Salida};
	% Señal portadora
	\draw (10, -5) node [ground]{} to [vsourcesin] (10,-3) node[ann,below=30,left=20]{Portadora};
\end{tikzpicture}
\end{document}