How can i plot this signal?

I have a signal like this v=240*sin(2*pi*f(t)*t) where f(t)=50+sin(t). My sampling frequency is 7500 Hz.How can i plot the above mentioned signal?I am getting an error while plotting.Expecting reply.

Answer 1

[Matt Fig]

f = @(t) 50+sin(t);
v = @(t) 240*sin(2*pi*t.*f(t));
t = 0:.001:1;
plot(t,v(t))

Answer 2

[Image Analyst]

Did you try the straightforward, obvious approach that just uses your equations to get f and then v?

% Get the times between 1 andnumberOfSeconds, inclusive:
% (Adjust parameters as needed.)
numberOfSeconds = 9
samplingRate = 7500 % Samples per second.
numberOfSamples = samplingRate * numberOfSeconds
t = linspace(0, numberOfSeconds, numberOfSamples);
% Get f:
f =50 + sin(t); 
% Get v:
v = 240 * sin(2*pi*f .* t);
% Plot:
plot(t, v);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);

[Matt Fig]

That picture is misleading. Try with

linspace(1,4*pi,8000);

Then again with 80000!

[Image Analyst]

Yeah, I know there's aliasing going on, but when I did it with just a few hundred samples, it looked like just a normal sine wave.

Answer 3

[Azzi Abdelmalek]

 te=1/7500;
 t=0:te:500*te;
 f=50+sin(t);
 v=240*sin(2*pi*f.*t);
 plot(t,v)

[Matt Fig]

This is sampled far too sparsely to give an accurate picture of the function.

[Azzi Abdelmalek]

his sampling frequency is 7500Hz that means a sample time is 1/7500 s

[Matt Fig]

Much nicer!