In this paper, the problem of approximating a linear time-invariant st
able system by a finite weighted sum of given exponentials is consider
ed. System identification schemes using Laguerre models are extended a
nd generalized to Kautz models, which correspond to representations us
ing several different possible complex exponentials. In particular, li
near regression methods to estimate this sort of model from measured d
ata are analyzed. The advantages of the proposed approach are the simp
licity of the resulting identification scheme and the capability of mo
deling resonant systems using few parameters. The subsequent analysis
is based on the result that the corresponding linear regression normal
equations have a block Toeplitz structure. Several results on transfe
r function estimation are extended to discrete Kautz models, for examp
le, asymptotic frequency domain variance expressions.