I have a signal with many frequencies. how to remove particular frequencies from it

hey guys,

I need to filter some particular frequencies from my signal, I have a signal which I know that has freq between 50 Hz to over 2450 Hz. now I just want to delete freq bigger than 2450 Hz from my signal. here is my code:

fs = 10000;     % Sampling rate [Hz]
Ts = 1/fs;     % Sampling period [s]
fNy = fs / 2;  % Nyquist frequency [Hz]
duration = 10; % Duration [s]
t = 0 : Ts : duration-Ts; % Time vector
noSamples = length(t);    % Number of samples
f = 0 : fs/noSamples : fs - fs/noSamples; % Frequency vector
vp1 = vp(:,:,1)+vp(:,:,2)+vp(:,:,3)+vp(:,:,4)+...
    vp(:,:,5)+vp(:,:,6)+vp(:,:,7)+vp(:,:,8)+...
    vp(:,:,9)+vp(:,:,10)+vp(:,:,11)+vp(:,:,12)+...
    vp(:,:,13)+vp(:,:,14)+vp(:,:,15)+vp(:,:,16)+...
    vp(:,:,17)+vp(:,:,18)+vp(:,:,19)+vp(:,:,20)+...
    vp(:,:,21)+vp(:,:,22)+vp(:,:,23)+vp(:,:,24);
x_fft = abs(fft(vp1));
hold on
%Plot
figure(1);
subplot(2,1,1);
plot(t,vp1);
subplot(2,1,2);
plot(f,x_fft);
xlim([0 fNy]);

and here is the result :

[KALYAN ACHARJYA]

vp ?

[Ajira]

positive sequence of voltage

Answer 1

[Marco Dellantonio]

You want to delete frequency above a certain thresold. You can simply check the index which corresponds to the thresold frequency and replace the magnitude of the Fourier Transform with 0 for every element of the modulus (a simple cicle is needed).

Answer 2

[Star Strider]

Use the lowpass function (R2018a and later).