Comparative study of 16 kbps adaptive predictive coders

In this paper, a comparative study of adaptive predictive coders operating at 16 Kbps is reported. In the first part of the paper, the different architectures are described, assuming both recursive and transversal approaches and several implementations of noise shaping concept. The second part of the paper gives the detailed results of the study. For each coder, two configurations have been considered, either including a pitch loop (long term prediction), or not. For each of them, both objective measures -in terms of signal to noise ratio - and subjective evaluations - provided by listening tests - are given. Obtained results about noise shaping techniques applied to predictive coders are in good agreement with previously reported ones. Moreover, it is shown that similar performances can be reached by using a transversal structure.