butterpass_eeglabdata.m

function [band_sig]=butterpass_eeglabdata(signal,band,srate)
% function to dobandpass filtering for specified band
% input:
% signal = time X channels;
% band= [start:stop] or [start stop];
% 
% D Hermes 2012

%automatic stuff:
% num_chans=1;

num_chans=size(signal,2); % number of channels
% 
% num_chans=size(signal,1) % number of channels
Rp = 3; Rs = 60; % third order Butterworth
delta = 0.001*2/srate;
low_p = band(2)*2/srate;
high_p = band(1)*2/srate;

high_s = max(delta, high_p - 0.1);
low_s = min(1-delta, low_p + 0.1);
[n_band, wn_band] = buttord([high_p low_p], [high_s low_s], Rp, Rs);
[bf_b bf_a] = butter(n_band, wn_band);

% fband=filtfilt(bf_b, bf_a, signal(:,84)); %band pass
band_sig=zeros(size(signal));
for k=1:num_chans
    % just for nice disp:
    if mod(k,5)==0,disp(strcat(num2str(k),'/',num2str(num_chans))),end %this is to tell us our progress as the program runs
    band_sig(:,k)=filtfilt(bf_b,bf_a, signal(:,k)); %band pass
end