Calculating the frequency of data

I have a data (length-time) that looks like this. I am trying to calculate the frequncy of this data. Is there any way that I can calcukate this frequncy based on the peak to peak position?

Answer 1

[Benjamin Thompson]

If you can do it manually, I like ginput. You use the mouse to select the points of interest and ginput returns the x and y values of those points from the plot.

>> t = 1:0.01:5;

>> x = sin(2*pi*4*t);

>> figure, plot(t, x);

>> [a, b] = ginput(2)

a =

1.8249

2.0645

b =

0.9913

0.9854

>> 1/(a(2)-a(1))

ans =

4.1731

[Sam J]

Thank you for your answer.

[Benjamin Thompson]

If this answer works for you please mark it as accepted.

[Sam J]

I have a lot of data like this to analyze. I am looking for a auomated way. Is there any to do it automatically?

[Benjamin Thompson]

Use the fast fourier transform or fft function in MATLAB to map an input signal to the frequency spectrum. The signal processing toolbox also has some helpful things like findpeaks and pspectrum. You can also type "lookfor" followed by a key word to find functions that do things you want in MATLAB.