Simple Convolution Plot Errors
2 views (last 30 days)
Show older comments
Anonomous
on 25 Feb 2016
Commented: Haribabu Kilari
on 28 Sep 2016
I am trying to plot a convolution example from my text book. Somewhere in the setting up of the plot dimensions/colors etc i made an error and i cannot find it. any help would be greatly appreciated.
The current compile error is on
axis ([tau (1) tau(end) -2.0 2.5]);
thank you.
% MS2p4.m : MATLAB Session 2, Program 4
% Script M-file graphically demonstrates the convolution process.
clc
clear
figure (1) % Create figure window and make visible on screen
x = inline('1.5*sin(pi*t).*(t>=0 & t<1)');
h = inline('1.5*(t>=0&t<1.5) - (t>=2&t<2.5)');
dtau = 0.005; tau = -1:dtau:4;
ti = 0; tvec = -.25:.1:3.75;
y = NaN*zeros(1, length (tvec)); % Pre-allocate memory
for t = tvec,
ti = ti+1; % Time index
xh = x(t-tau).*h(tau); lxh = length (xh);
y(ti) = sum(xh.*dtau); % Trapezoidal approximation of interal
subplot (2,1,1), plot(tau, h(tau), 'k-', tau, x(t-tau), 'k--', t, 0, 'ok');
axis ([tau (1) tau(end) -2.0 2.5]);
patch([tau(1:end-1); tau(1:end-1); tau (2:end); tau (2:end)],...
[zeros(1,lxh-1);xh(1:end-1);xh(2:end);zeros(1,lxh-1)],...
[.8 .8 .8], 'edgecolor', 'none');
c = get(gca, 'children'); set (gca, 'children', [c(2); c(3); c(4); c(1)]);
subplot (2, 1, 2), plot (tvec, y, 'k', tvec (ti), y(ti), 'ok');
xlabel ('t'); ylabel ('y(t) = \int h(\tau)x(t-\tau) d\tau');
axis ([tau(1) tau(end) -1.0 2.0]); grid;
drawnow;
axis ([tau(1) tau(end) -1.0 2.0]); grid;
drawnow;
end
0 Comments
Accepted Answer
Image Analyst
on 26 Feb 2016
Edited: Image Analyst
on 26 Feb 2016
You have a space between tau and (1) and (2:end), so it thinks there are two separate things, and then you end up having more than 4 elements in between the brackets. Get rid of that space. Fixed code:
axis ([tau(1) tau(end) -2.0 2.5]);
patch([tau(1:end-1); tau(1:end-1); tau(2:end); tau(2:end)],...
[zeros(1,lxh-1);xh(1:end-1);xh(2:end);zeros(1,lxh-1)],...
[.8 .8 .8], 'edgecolor', 'none');
2 Comments
More Answers (0)
See Also
Categories
Find more on Annotations in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!