Convert prediction filter polynomial to autocorrelation sequence
r = poly2ac(a,efinal)
r = poly2ac(a,efinal) returns the autocorrelation vector, r, corresponding to the autoregressive prediction filter polynomial, a, and the final prediction error, efinal. r is approximately equal to the autocorrelation of the output of a prediction filter with coefficients a. If a(1) is not equal to 1, poly2ac normalizes the prediction filter polynomial by a(1). 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 = 5.5917 -1.7277 -4.4231 4.3985 1.6426 -5.3126