In my code below, there is a marker in the legend. I just have two plots without any markers. How to remove these markers and just have the line be shown in the legend entry?
Here is my code:
\documentclass{book}
\usepackage{tikz}
\usepackage{pgfplots}
\clearpage
\pgfplotsset{minor grid style={dotted,gray!50}}
\pgfplotsset{major grid style={gray!50!black}}
\begin{filecontents*}{Noise.dat}
Freq Orig Filt
100.000, -79.374, -119.392
101.801, -79.858, -119.321
103.634, -78.587, -117.497
1000, -79.077, -117.437
1070.401, -78.735, -116.547
1090.335, -81.799, -119.065
11100.304, -82.298, -119.021
11300.309, -82.329, -118.511
115000.349, -81.744, -117.389
\end{filecontents*}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}[every plot/.append style={very thick}]
\begin{semilogxaxis}[width=14cm,height=10cm,
grid = both,
every major grid/.style={gray, opacity=0.7},
title = {},
xlabel={\emph{Offset Frequency (Hz)}},
ylabel={\emph{Phase Noise (dBc/Hz)}}]
\addplot table[mark = none, x index=0,y index=1,col sep=comma] {Noise.dat};
\addlegendentry{\emph{Original Phase Noise Data}}
\addplot table[mark = none, x index=0,y index=2,col sep=comma] {Noise.dat};
\addlegendentry{\emph{Filtered Noise Data}}
\end{semilogxaxis}
\end{tikzpicture}
\caption[Original and Filtered Response.]{Original and Filtered Response.}
\end{figure}
\end{document}