MATLAB代码如下：（参考书：Digital Signal Processing Using MATLAB, 3rd Edition 2011.下同）

连续时间信号：

t = 0:0.01:2;    % sample points from 0 to 2 in steps of 0.01

x = sin(2*pi*t); % Evaluate sin(2 pi t)

plot(t,x,'b');   % Create plot with blue line

xlabel('t in sec'); ylabel('x(t)'); % Label axis

title('Plot of sin(2\pi t)'); % Title plot

离散时间信号（火柴梗图）：

n = 0:1:40;  % sample index from 0 to 20

x = sin(0.1*pi*n); % Evaluate sin(0.2 pi n)

Hs = stem(n,x,'b','filled'); % Stem-plot with handle Hs

set(Hs,'markersize',4); % Change circle size

xlabel('n'); ylabel('x(n)'); % Label axis

title('Stem Plot of sin(0.2 pi n)'); % Title plot

将两者画在同一个图上：

t = 0:0.01:2; % sample points from 0 to 2 in steps of 0.01

tx = sin(2*pi*t); % Evaluate sin(2 pi t)

plot(t,tx,'b'); % Create plot with blue line

hold on

n = 0:1:40;  % sample index from 0 to 20

nx = sin(0.1*pi*n); % Evaluate sin(0.2 pi n)

Hs = stem(n*0.05,nx,'b','filled'); % Stem-plot with handle Hs

set(Hs,'markersize',4); % Change circle size

hold off

画在两个图上同时显示：

t = 0:0.01:2; % sample points from 0 to 2 in steps of 0.01

tx = sin(2*pi*t); % Evaluate sin(2 pi t)

subplot(2,1,1);

plot(t,tx,'b'); % Create plot with blue line

n = 0:1:40;  % sample index from 0 to 20

nx = sin(0.1*pi*n); % Evaluate sin(0.2 pi n)

subplot(2,1,2);

Hs = stem(n*0.05,nx,'b','filled'); % Stem-plot with handle Hs

set(Hs,'markersize',4); % Change circle size