import pylab
import scipy.signal
from spectrum import aryule
a = [1, -2.2137, 2.9403, -2.1697, 0.9606]
y = scipy.signal.lfilter([1], a, pylab.randn(1, 1024))
ar, variance, coeff_reflection = aryule(y[0], 20)
pylab.stem(range(1,21), ar)
pylab.title('Evolution of the first AR parameters')