I have data vibration in excel, the first row is time, and the second is vibration. I want to use fft to analyze the vibration. Because, i'm new to dsp, i don't know, what is sampling frecuency, etc. I searching and i found http://www.stem2.org/je/Excel_FFT_Instructions.pdf, but i still confused. Then, i searching again how to do fft in matlab using imported data from excel, and i found https://www.mathworks.com/matlabcentral/answers/329302-how-to-perform-fft-in-matlab-using-a-set-of-data-from-excel-sheet, again i don't know the sampling frequency and the other. How to do it? Thank you.
Thanks to @MattiP., i've been able to calculate fft using excel, now here is the graphic, how to know / analyse this?