如何设置这条蓝线，使其像图片上的那样？
这是我的代码，我尝试将样本从 90 更改为 130，但没有成功。
\begin{tikzpicture}[scale=0.8]
\begin{axis}
[xlabel=$t$,ylabel=$x(t)$,xmin=-5,xmax=5,ymin=-2,ymax=2,grid=major,grid style={solid}]
\addplot[roza,line width=1pt,smooth] expression{(sin(90*x))+0.5};
\addplot[domain=-5:5,blue,samples=126,line width=0.7pt] expression{sin(90*x)+0.4*rand};
\addplot[roza,line width=1pt, smooth]expression{(sin(90*x))-0.5};
\end{axis}
\end{tikzpicture}
看起来是这样的：
答案1
发布图像的复制版如下。
从代码中可以看出，所采用的方法是绘制从原始图像中提取的数据点。因此，它更像是一种再现随机数据序列的噱头，而不是它应该有的样子（我们永远不会知道吗？）。但是，正如我一开始所说的，这是为了再生产（即副本）。
滚动到 MWE 末尾查看相关部分。
\documentclass[]{article}
\begin{filecontents}{rand.dat}
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\end{filecontents}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\begin{document}
\centering
\begin{tikzpicture}
\begin{axis}[%
xlabel=$t$,
ylabel=$x(t)$,
xmin=-5,
xmax=5,
ymin=-2,
ymax=2,
grid=major,
grid style={solid},
samples=75
]
\addplot[red,line width=1pt,smooth] expression{(sin(90*x))+0.5};
\addplot[red,line width=1pt, smooth]expression{(sin(90*x))-0.5};
\addplot[blue,line width=0.7pt] table {rand.dat};
\end{axis}
\end{tikzpicture}
\end{document}