A wide-band speech-model process as a test signal

Some of the major problems in objective quality assessment of speech coding systems or in testing other adaptive speech transmission systems are the speaker dependence, reproducibility, and the comparability of the measurement results, if natural speech is used as the test signal. This problem can be avoided by using suitable speech-model processes. In this paper, we present a wide-band speech-model process, which includes the same long- and short-time characteristics as natural speech. The controlling part of the generator of this process involves several trained Markov chains (mc) to adapt the time-varying properties of the process to those of natural speech. Furthermore, special care is taken of the necessary probabilty density function (PDF) asymmetries, because the natural wide-band speech has an asymmetric PDF.