% Description : This code generates a noisy sine wave and then plots both.
%
% Author: Dr. C. Alex Simpkins
%
%
x=0:.05:6; %we create a vector for the x axis. Note how we specify jump distances between
%data points as 0.05 spacing rather than the default of 1
%note a semicolon prevents writing the results of the assignment to the screen
n=.2*randn(1,length(x)); %this generates the random noise data of length of the vector x
%the amplitude is reduced to 0.2
y=sin(x)+n; %now generate a sine wave, and add the noise to it
plot(x,y); %we plot x vs. y
xlabel('time (sec)'); %we add x and y labels, as well as a title. Take note of the quotes
ylabel('Amplitude (Volts)'); %for specifying text
title('Typical noisy signal')
hold on %the hold command allows us to plot additional lines to the same figure window without
%replacing the original plot
plot(x,sin(x),'r'); %plot the original sine wave
legend('Noisy signal','Ideal signal'); %create a legend to label the two signals