Find FFT from time domain in excel

I have a question about FFT. I just saved a file from my DSO, the extension is xxx.csv and I can open it with excel, actually this is a time domain. I want to know how to find FFT from that file. xxx.csv has 2 rows in excel. First row is source second (time), and the 2nd row is CH1 in Volt. These 2 rows have 3000 data coloumn vertically. What function should I write to find the FFT from that file? Thank you.....

Answer 1

[Geoff Hayes]

Nelson - you can use the csvread to read your data from file

 data = csvread('xxx.csv');

The above assumes that you are executing the above command in the folder where you file is located. The variable, data, will have two columns of 3000 elements each with the first column being the sample time (seconds), and the second column being the time domain data (volts).

Now see the examples at fft on how to use this function with your data. You have 3000 samples, but what is the sample rate (Fs)? Presumably your time data (first column) includes fractions of a second. How many seconds worth of data do you have? Is the time delta between each consecutive pair of samples time identical?