Try this filter:
signal = load('datee.txt'); % Signal Vector
signal = detrend(signal,0);
Fs = 10; % Sampling Frequency (Hz)
Ts = 1/Fs; % Sampling Interval (sec)
tv = linspace(0, 1, numel(signal))*Ts; % Time Vector
Fn = Fs/2; % Nyquist Frequency (Hz)
Wp = [0.503 0.523]/Fn; % Passband Frequency (Normalised)
Ws = [0.483 0.543]/Fn; % Stopband Frequency (Normalised)
Rp = 1; % Passband Ripple (dB)
Rs = 50; % Stopband Ripple (dB)
[n,Ws] = cheb1ord(Wp,Ws,Rp,Rs); % Filter Order
[z,p,k] = cheby1(n,Rs,Ws,'stop'); % Filter Design
[sossb,gsb] = zp2sos(z,p,k); % Convert To Second-Order-Section For Stability
figure(5)
freqz(sossb, 2^16, Fs) % Filter Bode Plot
filtered_signal = filtfilt(sossb, gsb, signal); % Filter Signal
figure(6)
subplot(2,1,1)
plot(tv, signal)
grid
subplot(2,1,2)
plot(tv, filtered_signal)
grid
This designs a narrow Chebyshev Type I bandstop filter. Experiment with the filter stopbands and passbands to get the result you want.
To use it with my previous code, append it to the end of my previous code, and substitute this assignment:
signal = load('datee.txt'); % Signal Vector
with this one:
signal = filtered_signal;
