Can please somebody check my code and tell me what I ma doing wrong. I am trying to write a code for AM modulated wave of amplitude A to plot N element array of displacement values.

delta_t=1/f_s start=0 step=t stop=(N-1)*delta_t t=start:step:stop A=input('enter amplitude of the wave'); fmod=input('enter modulation frequency'); fsig=input('enter signal frequency'); ym=A*sin(2*pi*fmod*t); ys=sin(2*pi*fsig*t); y=(A+ym)*sin(2*pi*fsig*t) subplot(3,1,1) plot(t,y);

Answer 1

[Jacob Ward]

First off, please try to stick to the guidelines for posting questions to this site. See this answer for help in that area:

https://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

While it's a little bit unclear what you are asking for, changing the multiply to a dot multiply in the line y=(A+ym).*sin(2*pi*fsig*t) got rid of the errors that I was seeing and at least produced some results. See below:

f_s = 200; 
t = .1; 
N = 2000;
delta_t=1/f_s;
start=0; 
step=t; 
stop=(N-1)*delta_t; 
t=start:step:stop;
A=input('enter amplitude of the wave'); 
fmod=input('enter modulation frequency'); 
fsig=input('enter signal frequency'); 
ym=A*sin(2*pi*fmod*t); 
ys=sin(2*pi*fsig*t); 
y=(A+ym).*sin(2*pi*fsig*t); % I changed the * in this line to a .*
% I also removed the subplot command because it's not needed
plot(t,y);

Is this what you were looking for?