Convert prediction filter polynomial to autocorrelation sequence
r = poly2ac(a,efinal)
r = poly2ac(a,efinal) returns the
r, corresponding to the autoregressive
prediction filter polynomial,
a, and the final prediction error,
r is approximately equal to the
autocorrelation of the output of a prediction filter with coefficients
a(1) is not equal to 1,
poly2ac normalizes the prediction filter polynomial by
a(1) cannot be 0.
Given a prediction filter polynomial,
a, and a final prediction error,
efinal, find the autocorrelation sequence.
a = [1.0000 0.6147 0.9898 0.0004 0.0034 -0.0077]; efinal = 0.2; r = poly2ac(a,efinal)
r = 6×1 5.5917 -1.7277 -4.4231 4.3985 1.6426 -5.3126
You can apply this function to both real and complex polynomials.
 Kay, Steven M. Modern Spectral Estimation. Englewood Cliffs, NJ: Prentice-Hall, 1988.
Usage notes and limitations:
See Variable-Sizing Restrictions for Code Generation of Toolbox Functions (MATLAB Coder).