def signal(x, yT, T):
Y=[]
fp=open('testt.txt', 'w')
fp.write('Xi\tYi\n')
for ins in x:
outs=(ins+T*yT)/(T+1)
Y.append(outs)
yT=outs
fp.write(str(ins)+'\t'+str(outs)+'\n')
fp.close
return Y
