function [FilteredECG] = preprocessing_v2(ECG,fs)
#uses notch filter
#this version is a testing version for eliminating 50 Hz power line
#noise
% ---- preprocess the data ----
FilteredECG=zeros(size(ECG));
lmedfilt=floor(12*fs/1000);
lmovavgkernel=8;
movavgkernel=ones(1,floor(lmovavgkernel*fs/1000))/lmovavgkernel;
%should it really be done before mqrs detection????
#noch filter 50Hz
#fs=samplingrate;
fs2=fs/2;
#[b,a]=pei_tseng_notch ( 50/fs2, 3/fs2 );
load notchfilter50Hz.txt
for i=1:4
FilteredECG(i,:)=removebaseline(ECG(i,:), fs);
FilteredECG(i,:)=medfilt1(FilteredECG(i,:),lmedfilt);
#FilteredECG(i,:)=filtfilt(movavgkernel,1,FilteredECG(i,:));
FilteredECG(i,:)=filtfilt(b,a,FilteredECG(i,:));
endfor
FilteredECG=saturate(FilteredECG);
end