New measurement methods for determining the transfer characteristics of telephone terminal equipment

Measurement methods are outlined for the assessment of the transfer characteristics of handsets and hands-free telephones or conference systems that are based on artificial head technologies. A suitable system approximating the radiation of the human mouth and the binaural receive characteristics is described. In addition to new acoustical transmitters and receivers, a more complex test procedure is required. A measurement method is proposed which is based on a new measurement signal approximating the human voice properties with respect to modulation, power density, probability density, and time structure. It permits the determination of different parameters relevant to the transmission of speech quality. Properties and applications of the measurement method are described