Combining 2 signals into 1

I'm trying to combine these signals but I'm not sure how.

   n = [0:1023];
   omega = 0.25*pi;
   xn = sin(omega*n);
  ns = sqrt(0.2)*randn(1,n);

[Rick Rosson]

What specifically do you mean by "combine"?

[Dick Rusell]

Put them on top of each other on the same graph.

Answer 1

[Image Analyst]

After seeing your clarification, I offer these two possibilities. Perhaps one of them is what you want:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
fontSize = 20;

% Setup
n = 100;
x=1:n;
omega = 0.25*pi;
xn = sin(omega*x);
ns = sqrt(0.2)*randn(1,n);

% Plot different scenarios, depending on what "combine" means.
% Plot both on same plot

% Plot with common y axis on left side
subplot(2,1,1);
plot(x, ns, 'r-', 'LineWidth', 2);
hold on
plot(x, xn, 'b-', 'LineWidth', 2);
xlabel('x', 'FontSize', fontSize);
ylabel('xn, ns', 'FontSize', fontSize);
title('xn and ns vs. x, one y axis', 'FontSize', fontSize);
grid on;
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);

% Plot each with separate y axis.
subplot(2,1,2);
plot(x, ns, 'r-', 'LineWidth', 2);
hold on
hPlots = plotyy(x, xn, x, ns);
xlabel('x', 'FontSize', fontSize);
ylabel(hPlots(1), 'xn', 'FontSize', fontSize);
ylabel(hPlots(2), 'ns', 'FontSize', fontSize);
title('xn and ns vs. x, separate y axes', 'FontSize', fontSize);
grid on;

If neither of these is what you want, then please clarify again -- there are other possibilities. See MATLAB Gallery for some of them.

[Image Analyst]

"other possibilities" -- such as the way Rick did it, which I just saw and is slightly different than my two ways.

Answer 2

[Rick Rosson]

Please try:

   plot(n,xn,n,ns);

For more info:

   >> doc plot