function y=enleve_drift(x);

[N,wn]=buttord(0.02,0.01,0.5,20);
[b,a]=butter(N,wn,'high');
y = filtfilt(b,a,x);
subplot(211)
plot(x)
title('signal')
subplot(212)
plot(y)
title('signal apres filtrage')
subplot(111)




