Comments on "On the design of pole-zero approximations using a logarithmic error measure"

The present paper comments on a paper by Blommer and Wakefield (IEEE Trans. Signal Processing, vol.42, no.11, p.3245-8, 1994 Nov.). The present author shows that the log spectral matching technique described in Blommer and Wakefield is equivalent to least-squares cepstral matching, whose application to the construction of pole-zero approximations was reported in an earlier publication. We review several key characteristics of the cepstral matching procedure and indicate that it is computationally much simpler than the log spectral matching technique.