Convert prediction filter coefficients to line spectral frequencies
lsf = poly2lsf(a)
lsf = poly2lsf(a) returns
lsf, of line spectral frequencies from
a, of prediction filter coefficients.
Given a vector,
a, of prediction filter coefficients, generate the corresponding line spectral frequencies.
a = [1.0000 0.6149 0.9899 0.0000 0.0031 -0.0082]; lsf = poly2lsf(a)
lsf = 0.7842 1.5605 1.8776 1.8984 2.3593
 Deller, John R., John G. Proakis, and John H. L. Hansen. Discrete-Time Processing of Speech Signals. New York: Macmillan, 1993.
 Rabiner, Lawrence R., and Ronald W. Schafer. Digital Processing of Speech Signals. Englewood Cliffs, NJ: Prentice-Hall, 1978.