Improved method for parameter estimation of complex sinusoids in noise

Using, respectively, the theory of resultants/subresultants (inner determinants) and the one-to-one correspondence between reactance functions and Hurwitz polynomials, a set of necessary conditions and also another set of necessary and sufficient conditions, which involve nonlinear constraints on the polynomial coefficients, are obtained for all the roots of the polynomial to lie on the unit circle and be distinct from each other. The results have potentials for leading to improvements over previous methods for estimating parameters of sinusoids in noise where the constraints imposed provided only necessary conditions which were linear in the polynomial coefficients