Potting sin() wave graph

Hi,

i am trying to plot three sign wave graph in one figure but the graphs are not coming out as intended.

wgn: Generate 60 random sample; Amplitude range -0.2 to 0.2

wgn2: wgn*3

A = 2 ;
f = 100;
n = (0:60);
fs = 2000;
x = A*sin(2*pi*n*(f/fs));

t = x/1000;
wgn = rand(1,61)*0.4-0.2;
wgn2 = wgn*3;

subplot (3,1,1)
plot(x,t,'m--d')
xlabel ('x')
ylabel ('time (ms)')
title ('Graph')
grid

subplot (3,1,2)
plot (wgn,t,'b-x')
xlabel ('wgn')
ylabel ('time (ms)')
grid

subplot(3,1,3)
plot((x+wgn2),t,'g-*')
xlabel ('x+wgn2')
ylabel('time (ms)')
grid

[Alberto Mora]

Please explain better the problem

Answer 1

[Ayush Laddha]

From your explanation of the question, I infer that you want to have all 3 graphs in a single plot. You can make use of the hold on and hold off commands to do so. You can also use the legend function to specify appropriate details for every line. You also mentioned in the question that you wanted to have 60 random samples however, I can see that your code generates 61 random samples. I have fixed the code for that too.

A = 2; 
f = 100; 
n = (1:60); 
fs = 2000; 
x = A*sin(2*pi*n*(f/fs)); 
t = x/1000; 
wgn = rand(1,60)*0.4-0.2; 
wgn2 = wgn*3; 
plot(x,t,'m--d') 
hold on 
plot (wgn,t,'b-x') 
plot((x+wgn2),t,'g-*') 
grid on 
title('Graph') 
ylabel('time') 
legend("x", "wgn", "x+wgn2", "Location", "northwest") 
hold off 

You can refer to the documentation of the functions for further info –

https://www.mathworks.com/help/matlab/ref/hold.html

https://www.mathworks.com/help/matlab/ref/legend.html