# How to perform FFT analysis of a signal in MATLAB SHARE

The content is basically the same, but we introduce a few details such as how to create data.

Please check this out as well!

The MATLAB manual is still confusing, so I will summarize it. You can paste the code together into the command window.

intended audience

• Those who want to do FFT analysis in MATLAB
• ## Prepare data in Excel

As an example here, we have three sin curves in Excel, each with a different frequency.
In this case, 1 Hz, 3 Hz, and 10 Hz were used.
The signal in column E (yellow), which is the sum of the two, is the target of the analysis. Save the file as a CSV file, leaving only columns A and E.

The formulas for each column are as follows.

• Column B "=SIN(2*PI()*A2)"
• Column C "=SIN(2*PI()*3*A2)"
• Column D "=SIN(2*PI()*10*A2)"
• Column E "=SUM(B2:D2)"

You can copy and paste it directly into Excel. I will also upload the Excel file to my Github so you can use that as well.
https://github.com/buono/MATLAB_FFT

## Data Import in MATLAB

Import t and sum as arrays in MATLAB as follows, respectively.  ## Set the signal and plot

In this case, the following code was used to create signals up to 4 seconds at 0.002 second intervals.

[crayon] T = 0.002; % sample period
L = 1001; % Number of signal points (note that it is not time!)
t = (0:L-1)*T; % time vector

Y = fft(sum);
P2 = abs(Y/L);.
P1 = P2(1:L/2+1);.
P1(2:end-1) = 2*P1(2:end-1);

Fs = 1/T;.
F = Fs*(0:(L/2))/L;.
plot(F,P1);.
[/crayon]

As shown below, we see peaks at 1Hz, 3Hz, and 10Hz. 