Up to now, the general problem of speech quality assessment, especially of coded speech signals has been accomplished by using highly standardized human listening tests. Because of several shortcomings of these subjective procedures many objective approaches have been proposed in the past. Each of the objective measures tries to avoid most of these drawbacks. However, one of the major problems is still left out of account by all of them: The test results depend on the underlying set of speech-data (e. g. speaker dependence!), since they use natural speech as the test signal. Of course, this problem is unavoidable in the case of subjective procedures, but there is no reason to accept it in the case of objective measurements. So, in this paper we propose a test signal, which is a special random process. It is shown that the important characteristics of this process agree with those of natural speech. Furthermore, the results of a study of objective quality-measures involving a speech-model process as the test signal are presented.
Bibliographic reference. Halka, Ulrich (1991): "Speech-model processes for objective quality measurements of speech-coding systems", In EUROSPEECH-1991, 887-890.