Estimation of the Quality Dimension “Dire Instrumental Assessment

The presented work aims at an instrumental method for the assessment of speech-quality of modern telecommunication networks that features two functions: the prediction of a system’s overall speech-quality as well as the analysis of the overall speechquality. The introduced method is based on the estimation of quality dimensions, each describing a particular characteristic relevant for the quality of speech signals. For narrowband telephonespeech three relevant dimensions have been identified: “directness/frequency content” , “continuity”, and “noisiness”. The estimates of the single dimensions allow for an analysis of speech quality while together forming a model for the overall quality. This paper presents a method for the estimation of the quality dimension “directness/frequency content”. The estimator is based on two parameters considered suitable to measure “directness/frequency content” of a speech signal y(k) that has been transmitted over a telecommunication system. The estimates d DF of this dimension show correlations of ρ > 0.93 with the results of corresponding auditory tests.