from spectrum import *
from pylab import *

ar, P, k = aryule(marple_data, 15, norm='biased')
psd = arma2psd(ar)
plot(linspace(-0.5, 0.5, 4096), 10 * log10(psd/max(psd)))
axis([-0.5, 0.5, -60, 0])