NDatei = 3; 
source='C:\Users\Praktikum\Documents\MATLAB\20140512-0013';
for k=1:NDatei
    fileLocator=fullfile(source, sprintf('20140512_0013-%03d.txt',k)) ;
    data=textread(fileLocator, 'txt') ;
    [pks,len]=findpeaks(data,'MINPEAKHEIGHT',2.0);
end