Hamming window around a specific frequency

Hello

So, I'm in need of a little help concerning the hamming windowing of a signal. In fact, I realised the windowing, but it's over the full length of the signal, which doesn't suit my needs.

Instead, I need the window to be specifically around a selected frequency, let's say 50 Hz for instance, to denoise my signal and accentuate the frequency in question. The problem is that I can't manage to specify the length of the window so that it's set around a desired frequency. Especially when I'm windowing the signal in time domain (so introducing a frequency is not so obvious) and realise the FFT of the convoluted signal afterwards.

Here's the code :

clear all ;
close all ;
clc ;

   n1 = 1000;
    Fe = 12000;

    t = (0:n1-1)/Fe;

    sig = sin(2*pi*50*t) ;

    L = length (sig); 
    nfft = 2^nextpow2(L);
    s_Hamming = s2.*hamming(L); 
    Sfft_Hamming = fft(s_Hamming,nfft)/L;

    mYdft = (Sfft_Hamming);
    mYdft = mYdft (1:nfft/2+1);
    mYdft (2:end-1) = 2*mYdft(2:end-1);

    f = Fe/2*linspace(0,1,nfft/2+1); 

    figure 
    plot(f,mYdft) 
    grid on
    title('Spectre avec fenètre de Hamming ');
    xlabel('Frequence'); 
    ylabel('Amplitude');

Thank you for any kind of help.

Answer 1

[Star Strider]

MathWorks already did this for you!

See: Remove the 60 Hz Hum from a Signal. Just make the change from 60 Hz to 50 Hz and you have the filter you want.