I need some help with the Fourier transformation of my data.
My original data is a Distance VS Time:
upon doing a Fourier Transform, I get the following:
I understand that normally after a Fourier transform the data is translated to amplitude/power VS frequency
But I am failing to understand what it is showing on the two axis? .
Also why some of the values are negative when my original data has all positive values?
After plotting the absolute values I get the following:
So now I can recognize that the x- axis is
time, but I still cannot make out the y - axis, is it
Performed a FFTSHIFT so it looks more like this:
which i think is a proper representation except it is still maintaining the same x -axis.