Speech quality in modern Telecommunications

摘要

In the context of telecommunications one of the most important measuring objects is speech quality. Apart from communicative aspects (e.g., way of speaking, listening and interacting behaviour) speech quality can be affected by a number of system parameters of a modern telecommunication service. These parameters are, for example, related to the transmission line (e.g., coders or packet losses), to terminals (e.g., handsets, head-sets, hands-free terminals) and also to new speech technology devices being coupled to transmission systems and terminals (e.g., speech synthesisers, speech recognisers, dialogue systems). In all these cases the quality of the transmitted speech signal depends on these individual system elements and their integration into a telecommunication service. Practically, speech quality is the result of a perception and judgement process in a communication context. In order to obtain data on perceived quality, measurements are performed. In principle, these measurements can either be carried out with subjects (auditory measurements) or algo-rithmically (instrumental measurements). Auditory measurements aim at putting to terms otherwise highly individual and sometimes even anonymous perceptual quality events, and instrumental measurements aim at modelling or predicting these. It is the aim of this contribution to discuss the state-of-the-art of auditory speech quality measurements in telecommunications in view of instrumental measurements. However, what is being said can be applied to different other fields dealing with acoustic/auditory measuring objects as well (e.g., product sound quality).