How to apply bandpass filter

% Load your signal matrix
% Assuming 'signalMatrix' is your matrix where each row is a signal
% Example: signalMatrix = rand(100, 1000); % 100 rows (signals) and 1000 columns (samples)

% Sampling frequency (Hz)
Fs = 20;

% Design a bandpass filter with a passband of 0.34 to 1 Hz
bpFilt = designfilt('bandpassiir', 'FilterOrder', 4, ...
                    'HalfPowerFrequency1', 0.34, ...
                    'HalfPowerFrequency2', 1, ...
                    'SampleRate', Fs);

% Initialize the filtered signal matrix
filteredSignalMatrix = zeros(size(signalMatrix));

% Apply the filter to each row
for k = 1:size(signalMatrix, 1)
    filteredSignalMatrix(k, :) = filtfilt(bpFilt, signalMatrix(k, :));
end

% Plot the original and filtered signals (for a selected row)
selectedRow = 1; % Choose a row to plot
figure;
subplot(2, 1, 1);
plot(signalMatrix(selectedRow, :));
title('Original Signal');
xlabel('Time (samples)');
ylabel('Amplitude');

subplot(2, 1, 2);
plot(filteredSignalMatrix(selectedRow, :));
title('Filtered Signal (Bandpass 0.34 - 1 Hz)');
xlabel('Time (samples)');
ylabel('Amplitude');