generate sine waves that appears after one another

Hello Everyone,

I want to generate sine waves in while loop with changeable values. The Problem is that with each repetition, a new signal is being generated. What i want is that the new Signal appears infront of the old one, so if my time is 1 sec, and i have the magnitude 1, the first signal should be in time intervall (0-1) with 1 magnitude and the next signal from (1-2) with the increased magnitude.

I have written the following code:-

f = 1;

a = 0.1;

Fs = 1000;

t1 = 1;

figure;

while 1 % Runs until you press Ctrl-c

t = 0 : 1/Fs :t1-1/Fs;

x = a * sin(2 * pi * f * t);

plot(t, x);

drawnow; % Give Matlab a chance to display changes

t1 = t1 + 1;

a=a+0.1;

end

If you have any ideas, i would be happy if you share with me.

Regards

Ali

Answer 1

[Pratyush Swain]

hi @Ali Albaidhani,

I believe you want to visualise the various amplitudes of sin wave in continous segments, that is the first signal should be in time intervall (0-1) with 1 magnitude and the next signal from (1-2) with the increased magnitude and so on.

As mentioned by @Jan, you can use the axes command to add to the same plot and you can also follow the given method to visualize in a better manner

f  = 1;
a  = 0.1;
Fs = 1000;
t1 = 1;
figure;
axes('NextPlot', 'add');
while 1 % Runs until you press Ctrl-c  
    %since we want to visualise the new amplitude in the segment-[t1-1,t1]%
    t_array  = t1-1 : 1/Fs :t1-1/Fs;
    x  = a * sin(2 * pi * f * t_array);
    plot(t_array, x);
    %add pause to visualise the graph as amplitude grows%
    pause(1);
    t1 = t1 + 1;
    a=a+0.1;
end

Hope this helps and satisfies your requirements.

Answer 2

[Jan]

figure;
% Insert this:
axes('NextPlot', 'add');   % Equivalent to: hold('on')
...    

Otherwise the plot() command clears its axes before plotting.

Answer 3

[Neeraj Mirji]

The following code will generate the new sine wave in the same plot.

f  = 1;
a  = 0.1;
Fs = 1000;
t1 = 1;
figure;
while 1   % Runs until you press Ctrl-c  
   t  = (t1-1) : 1/Fs :t1-1/Fs;
   x  = a * sin(2 * pi * f * t);
   plot(t, x);
   hold on;
   drawnow;   % Give Matlab a chance to display changes
   t1 = t1 + 1;
   a=a+0.1;
end

Hope it helps.

[Ali Albaidhani]

Thank you for your help