How to rapresent a signal and filter it?

I have a signal vector x, associated with a time vector t. I want to: ( 1 ) do the FFT and rapresent the resulting vector FFT versus the frequency; ( 2 ) filter the frequency with a highpass filter F(omega) = (omega/threshold) ./ sqrt(1+(omega/threshold).^2 ), and display in the same plot as before the filtered FFT; ( 3 ) reconstruct the signal from the filtered FFT. I searched in the whole internet but everyone is telling a different code, and nobody is telling WHY the code is written like that. Could you help me? Thanks a lot.

Answer 1

[Abhishek Ballaney]

https://in.mathworks.com/help/matlab/ref/fft.html