我想绘制脉冲总和，以描绘通过引入 ISI 的通信信道传输的二进制脉冲。我可以通过围绕 \addplot 命令放置一个 \foreach 循环来绘制单个脉冲，为每个脉冲添加一个图，如以下代码所示：
\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{positioning,arrows,shapes.arrows,shapes.geometric,calc,decorations.markings,patterns}
\usepackage{ifthen}
\usepackage{pgfplots}
\setbeamertemplate{navigation symbols}{}
%%%%%%%%%%%%%%%%%%%%
% Draw the user bits
\newcommand{\userBits}[3]{
% #1 the location west anchor of the bit array
% #2 a base label identifying this set of bits, eg: userBits or parityBits
% #3 the contents of the foreach loop that creates the bit array eg: a/1/0,b/1/1,c/0/2
% The first component is part of the label for the node box created that holds the bit
% The second component is the contents of the box that is written onto the page
% The third component is needed for compatibility with the drawIndividualWaveforms function
% it is not used in this function, but should still be there for compatibility.
\coordinate(O) at ($#1$);
\foreach\i/\j/\k in {#3}{
\node [bitBox,fill=blue!15] at (O)(#2\i){\j};
\coordinate(O) at (#2\i.0);
}
}
\newcommand{\drawIndividualWaveforms}[3]{
% #1 the location of the plot of individual waveforms
% #2 a label for this node
% #3 the contents of the for loop holding 3 components such as a/+/0:
% first component is a sublabel for this particular bit
% second component is the value of the bit either + or -
% third component is a k index indicating the delay of this wave pulse.
\node at ($#1$){\tikz{
\begin{axis} [axis lines =left,
width=6cm, height=2.7cm,
xtick=\empty,xticklabel=\empty,
ytick=\empty,yticklabel=\empty,
axis x line = middle,
ymin=-1.1, ymax=1.1,
xmin=0, xmax=7,
]
\foreach\i/\j/\k in{#3}{
\ifthenelse{\equal{\j}{+}}{
\addplot[domain=\k-1:\k+1,
samples=21,] {exp(-(x-\k)*(x-\k)*4)}; %{0.5*cos(180*x-180*\k)+0.5};
}{
\addplot[domain=\k-1:\k+1,
samples=21,] {-exp(-(x-\k)*(x-\k)*4)}; %{-0.5*cos(180*x-180*\k)-0.5};
}
}
\end{axis}
}};
}
\newcommand{\drawCombinedWaveforms}[3]{
% #1 the location of the plot of individual waveforms
% #2 a label for this node
% #3 the contents of the for loop holding 3 components such as a/+/0:
% first component is a sublabel for this particular bit
% second component is the value of the bit either + or -
% third component is a k index indicating the delay of this wave pulse.
\node at ($#1$){\tikz{
\begin{axis} [axis lines =left,
width=6cm, height=2.7cm,
xtick=\empty,xticklabel=\empty,
ytick=\empty,yticklabel=\empty,
axis x line = middle,
ymin=-1.1, ymax=1.1,
xmin=0, xmax=7,
]
\def\k{5}
\addplot[domain=0:7,samples=101]{
\foreach\i/\j\k in {#3}{
+exp(-(x-\k)*(x-\k)*4)
}
};
\end{axis}
}};
}
\pgfplotsset{compat=1.9}
\tikzset{>=stealth,
signalLabel/.style={text centered,font=\scriptsize,above,align=center},
boundingBox/.style={use as bounding box},
channelModule/.style={scale=.7,draw,top color=blue!30,align=center,inner sep=0.25cm,minimum height=1.2cm,node distance=0.75cm,minimum width=1.5cm},
bitBox/.style={anchor=180,draw,font=\scriptsize,inner sep=0,minimum width=0.33cm,minimum height=0.4cm}
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Begin document %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\newcommand{\channelSubFrame}[2]{
% Create a subframe for the animation demonstrating the parity check ENCODING process
% #1 Flag for the contenst of the channel box. 0: Channel. 1: Raised cosine pulse 2: raised cosine pulse AND draw the summation of the pulses rather than individual pulses
% #2 channel bits as input to the channel
\begin{frame}{Intersymbol Interference (ISI) Channel}
\begin{tikzpicture}
\path[boundingBox](0,0) rectangle ++(11,6); % Set the BB
\ifthenelse{\equal{#1}{0}}{
\node[channelModule,scale=1.4] at (4.5,5)(channel){Channel};
}{
\node[channelModule,inner sep=0.3cm] at (4.5,5)(channel){ISI Channel};
}
\draw[<-](channel.180)--node[above,signalLabel]{Channel bits $\mathbf{c}_k$}++(-4,0);
\draw[->](channel.0)--node[above,signalLabel]{Readback waveform $\mathbf{r}_k$}++(5,0);
\ifthenelse{\equal{#2}{}}{}{ % Only try to draw the user bits and waveforms if a set of bits (#2) has been provided by the caller
\userBits{(channel.south west)+(-3.0,0.0)}{channelBit}{#2} % Draw the user bits at the channel input
\ifthenelse{\equal{#1}{1}}{ % if equal to 1, then draw the separated pulses
\drawIndividualWaveforms{(channel.south east)+(2.5,-0.25)}{channelWaveform}{#2} % Draw the waveform consisting of the individual components of the impulse response
}{ % if equal to 2 then draw the combined waveform.
\drawCombinedWaveforms{(channel.south east)+(2.5,-0.25)}{channelWaveform}{#2} % Draw the waveform consisting of the summation of the components of the impulse response
}
}
\end{tikzpicture}
\end{frame}}
\channelSubFrame{1}{}
\channelSubFrame{1}{a/+/1}
\channelSubFrame{1}{a/+/1,b/--/2}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3,d/+/4}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3,d/+/4,e/--/5}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3,d/+/4,e/--/5,f/+/6}
\end{document}
我可以在同一张图上绘制多个脉冲，但无法将这些脉冲的总和绘制成单个波形。我尝试将 \foreach 循环放在 \addplot 中，如我尝试定义的 \drawCombinedWaveforms 命令中所示，但没有成功。任何帮助都非常感谢！谢谢
答案1
这是累积函数的一种方法。注意应该不是nest tikzpicures，完全没有必要，您可以使用 键shift移动轴。除此之外，还有几件事可以更改，例如 pgfplots 兼容版本。
\documentclass{beamer}
\usepackage{ifthen}
\usepackage{pgfplots}
\usetikzlibrary{positioning,arrows,shapes.arrows,shapes.geometric,calc,decorations.markings,patterns}
\setbeamertemplate{navigation symbols}{}
%%%%%%%%%%%%%%%%%%%%
% Draw the user bits
\newcommand{\userBits}[3]{
% #1 the location west anchor of the bit array
% #2 a base label identifying this set of bits, eg: userBits or parityBits
% #3 the contents of the foreach loop that creates the bit array eg: a/1/0,b/1/1,c/0/2
% The first component is part of the label for the node box created that holds the bit
% The second component is the contents of the box that is written onto the page
% The third component is needed for compatibility with the drawIndividualWaveforms function
% it is not used in this function, but should still be there for compatibility.
\coordinate(O) at ($#1$);
\foreach\i/\j/\k in {#3}{
\node [bitBox,fill=blue!15] at (O)(#2\i){\j};
\coordinate(O) at (#2\i.0);
}
}
\newcommand{\drawIndividualWaveforms}[3]{
% #1 the location of the plot of individual waveforms
% #2 a label for this node
% #3 the contents of the for loop holding 3 components such as a/+/0:
% first component is a sublabel for this particular bit
% second component is the value of the bit either + or -
% third component is a k index indicating the delay of this wave pulse.
\begin{axis} [shift={($#1+(0,-1cm)$)},axis lines =left,
width=6cm, height=2.7cm,
xtick=\empty,xticklabel=\empty,
ytick=\empty,yticklabel=\empty,
axis x line = middle,
ymin=-1.1, ymax=1.1,
xmin=0, xmax=7,
]
\foreach\i/\j/\k in{#3}{
\ifthenelse{\equal{\j}{+}}{
\addplot[domain=\k-1:\k+1,
samples=21,] {exp(-(x-\k)*(x-\k)*4)}; %{0.5*cos(180*x-180*\k)+0.5};
}{
\addplot[domain=\k-1:\k+1,
samples=21,] {-exp(-(x-\k)*(x-\k)*4)}; %{-0.5*cos(180*x-180*\k)-0.5};
}
}
\end{axis}
}
\newcommand{\drawCombinedWaveforms}[3]{
% #1 the location of the plot of individual waveforms
% #2 a label for this node
% #3 the contents of the for loop holding 3 components such as a/+/0:
% first component is a sublabel for this particular bit
% second component is the value of the bit either + or -
% third component is a k index indicating the delay of this wave pulse.
\begin{axis} [shift={($#1+(0,-1cm)$)},axis lines =left,
width=6cm, height=2.7cm,
xtick=\empty,xticklabel=\empty,
ytick=\empty,yticklabel=\empty,
axis x line = middle,
ymin=-1.1, ymax=1.1,
xmin=0, xmax=7,
]
\def\k{5}
\def\myf{0}
\foreach\i/\j/\k in {#3}{
\ifthenelse{\equal{\j}{+}}{
\xdef\myf{\myf+exp(-(x-\k)*(x-\k)*4)}
}{
\xdef\myf{\myf-exp(-(x-\k)*(x-\k)*4)}
}
}
\addplot[domain=0:7,samples=101,color=blue]{\myf};
\end{axis}
}
\pgfplotsset{compat=1.9}
\tikzset{>=stealth,
signalLabel/.style={text centered,font=\scriptsize,above,align=center},
boundingBox/.style={use as bounding box},
channelModule/.style={scale=.7,draw,top color=blue!30,align=center,inner sep=0.25cm,minimum height=1.2cm,node distance=0.75cm,minimum width=1.5cm},
bitBox/.style={anchor=180,draw,font=\scriptsize,inner sep=0,minimum width=0.33cm,minimum height=0.4cm}
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Begin document %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\newcommand{\channelSubFrame}[2]{
% Create a subframe for the animation demonstrating the parity check ENCODING process
% #1 Flag for the contenst of the channel box. 0: Channel. 1: Raised cosine pulse 2: raised cosine pulse AND draw the summation of the pulses rather than individual pulses
% #2 channel bits as input to the channel
\begin{frame}{Intersymbol Interference (ISI) Channel}
\begin{tikzpicture}
\path[boundingBox](0,0) rectangle ++(11,6); % Set the BB
\ifthenelse{\equal{#1}{0}}{
\node[channelModule,scale=1.4] at (4.5,5)(channel){Channel};
}{
\node[channelModule,inner ysep=0.7cm,inner xsep=0.3cm] at (4.5,5)(channel){ISI Channel};
}
\draw[<-](channel.180)--node[above,signalLabel]{Channel bits $\mathbf{c}_k$}++(-4,0);
\draw[->](channel.0)--node[above,signalLabel]{Readback waveform $\mathbf{r}_k$}++(5,0);
\ifthenelse{\equal{#2}{}}{}{ % Only try to draw the user bits and waveforms if a set of bits (#2) has been provided by the caller
\userBits{(channel.south west)+(-3.0,0.0)}{channelBit}{#2} % Draw the user bits at the channel input
\ifthenelse{\equal{#1}{1}}{ % if equal to 1, then draw the separated pulses
\drawIndividualWaveforms{(channel.south east)+(2.5,-0.25)}{channelWaveform}{#2} % Draw the waveform consisting of the individual components of the impulse response
}{ % if equal to 2 then draw the combined waveform.
\drawCombinedWaveforms{(channel.south east)+(2.5,-0.25)}{channelWaveform}{#2} % Draw the waveform consisting of the summation of the components of the impulse response
}
}
\end{tikzpicture}
\end{frame}}
\channelSubFrame{1}{}
\channelSubFrame{1}{a/+/1}
\channelSubFrame{1}{a/+/1,b/--/2}
\channelSubFrame{0}{a/+/1,b/--/2}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3}
\channelSubFrame{0}{a/+/1,b/--/2,c/--/3}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3,d/+/4}
\channelSubFrame{0}{a/+/1,b/--/2,c/--/3,d/+/4}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3,d/+/4,e/--/5}
\channelSubFrame{0}{a/+/1,b/--/2,c/--/3,d/+/4,e/--/5}
\channelSubFrame{1}{a/+/1,b/--/2,c/--/3,d/+/4,e/--/5,f/+/6}
\channelSubFrame{0}{a/+/1,b/--/2,c/--/3,d/+/4,e/--/5,f/+/6}
\end{document}
