PSD of a time function

Hello everyone,

I have the acceleration data collected from an accelerometer, and the acquisition time, the acceleration vs time graph is shown in the following image:

My question is, from this graph, how could I calculate in Matlab the PSD function in the frequency domain, from the temporal function shown above?

As an example of the practical problem, I used this code to generate the graph shown:

t = 0:.001:0.25;
x = sin(2*pi*50*t) + sin(2*pi*120*t);
plot(t,x)

Thanks in advance!

[dpb]

See example at doc fft

[Daniel González]

Thanks for your answer. And how could I obtain the PSD function?

[dpb]

That's what the example shows, specifically...PSD via FFT