documentclass[a4paper,fleqn,leqno]{article}
usepackage{polyglossia}
usepackage{tikz,tikz-3dplot,graphicx}
usepackage{array,multirow,tabu}
newcolumntype{C}[3]{@{hspace*{#1}}>{centeringarraybackslash}p{#2}@{hspace*{#3}}}
newcolumntype{R}[2]{>{raggedleftarraybackslash}p{#1}@{hspace*{#2}}}
newcolumntype{L}[2]{@{hspace*{#1}}>{raggedrightarraybackslash}p{#2}}
begin{document}

{renewcommandarraystretch{1.1}
begin{tabular}{|C{0pt}{100pt}{0pt}|C{0pt}{200pt}{0pt}|}
hline
multicolumn{1}{|C{0pt}{100pt}{0pt}|}{Modulační signál} & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \
hline
moduluje amplitudu nosného signálu & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \
hline
moduluje frekvenci nosného signálu & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \
hline
end{tabular}}\[1cm]

{tabulinesep=1.2mm
begin{tabu}{|c|c|}
hline
Modulační signál & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \hline
moduluje amplitudu nosného signálu & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \hline
moduluje frekvenci nosného signálu & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \hline
end{tabu}}

end{document}

tikzset{my pic adjust/.style={%%
  baseline=(current bounding box.center),
  execute at end picture={path (current bounding box.north) -- ++ (0,4pt);
                          path (current bounding box.south) -- ++ (0,-4pt);
                          }%
  }}

tikzset{my pic adjust/.style={%%
  baseline=(my center),
  execute at end picture={path (current bounding box.north) -- ++ (0,4pt);
                          path (current bounding box.south) -- ++ (0,-4pt);
                          path (current bounding box.center) -- ++ (0,#1) coordinate (my center);
                          }%
  },
 my pic adjust/.default=0pt,
}

documentclass[a4paper,fleqn,leqno]{article}
usepackage{polyglossia}
usepackage{tikz,tikz-3dplot,graphicx}
usepackage{array,multirow,tabu}
newcolumntype{C}[3]{@{hspace*{#1}}>{centeringarraybackslash}p{#2}@{hspace*{#3}}}
newcolumntype{R}[2]{>{raggedleftarraybackslash}p{#1}@{hspace*{#2}}}
newcolumntype{L}[2]{@{hspace*{#1}}>{raggedrightarraybackslash}p{#2}}
tikzset{my pic adjust/.style={%%
  baseline=(my center),
  execute at end picture={path (current bounding box.north) -- ++ (0,4pt);
                          path (current bounding box.south) -- ++ (0,-4pt);
                          path (current bounding box.center) -- ++ (0,#1) coordinate (my center);
                          }%
  },
my pic adjust/.default=0pt,
}

begin{document}

{renewcommandarraystretch{1.1}
begin{tabular}{|C{0pt}{100pt}{0pt}|C{0pt}{200pt}{0pt}|}
hline
multicolumn{1}{|C{0pt}{100pt}{0pt}|}{Modulační signál} &
  tikz[my pic adjust=-2pt] draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \
hline
moduluje amplitudu nosného signálu & tikz[my pic adjust=4pt] draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \
hline
moduluje frekvenci nosného signálu & tikz[my pic adjust=4pt] draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \
hline
end{tabular}}\[1cm]

{tabulinesep=1.2mm
begin{tabu}{|c|c|}
hline
Modulační signál & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \hline
moduluje amplitudu nosného signálu & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \hline
moduluje frekvenci nosného signálu & tikz draw[domain=-(pi/2):((7/2)*pi),smooth,variable=x,thick,scale=0.5] plot ({x},{sin(x r)}); \hline
end{tabu}}

end{document}

documentclass[a4paper,fleqn,leqno]{article}
usepackage{polyglossia}
usepackage{tikz}
usepackage{makecell, tabularx}

begin{document}

begin{center}
setcellgapes{5pt}
makegapedcells
tikzset{line/.style={draw=red, very thick, domain=-pi/2:7*pi/2, samples=60}}

begin{tabularx}{.88linewidth}{| >{raggedright}X | l |}
    hline
Modulačnínewline
signál
    &   tikz[baseline=(current bounding box.center)]
        draw [line] plot (0.5*x,{sin(x r)});     \
    hline
moduluje amplitudu nosného signálu
    &   tikz[baseline=(current bounding box.center)]
        draw[line] plot (0.5*x,{sin(x r)});      \
    hline
moduluje frekvenci nosného signálu
    &   tikz[baseline=(current bounding box.center)]
        draw[line] plot (0.5*x,{sin(x r)});      \
    hline
end{tabularx}
end{center}
end{document}