MATLAB: How can i plot a sine wave which is 5*sin(2*pi*50*t) for 20 seconds and 5*sin(2*pi*55*t) for next 30 seconds and again repeating 5*sin (2*pi*50*t)

digital signal processingsignal processing

 i need to plot a sine wave of 5*sin(2*pi*50*t) for 20 seconds and 5*sin(2*pi*55*t) for 21 to 50 seconds..how can i plot a above mentioned  signal using matlab programme?

Best Answer

Your title has something very different from your actual post, so I'm not sure what you actually want. And following your post, did you really want a 1 second gap with no sine wave? This does want you state in the actual body of your post.
 t = 0:1/200:50;
 x = zeros(size(t));
 x = 5*sin(2*pi*50*t).*(t<=20)+5*sin(2*pi*55*t).*(t>20);
 plot(t,x)
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