poly2ac Convert prediction polynomial to autocorrelation sequence. R = poly2ac(a,efinal) a: input prediction polynomial with 1st element 1 (if not, poly2ac normalizes it to 1 before proceeding). efinal: input prediction error r: output autocorrelation sequence This function obtains the underlying autocorrelation sequence that would best fit a linear prediction filter described by the denominator polynomial and the numerator scaling. The filter is H(z) = efinal/(a(1) + a(2) x z a(3) x z^2 ... a(n) x z^n-1) ac2poly poly2rc rc2poly rc2ac ac2rc Parthe Pandit S. Kay, Modern Spectral Estimation, Prentice Hall, N.J., 1987, Chapter 6.