Abstract
In order to measure the telephone transmission quality, the scale of naturalness which differs form that of articulation or intelligibility, was considered. Using this, evaluation was made on the effects of the factors of the transmitting system containing the distortions of filtering and non-linearity. In this report, the measuring scale for the naturalness of a certain talker was determined as the degree of difference of the talker's voice from the undistorted reference state of his original voice. For scaling of such qualities, we used the Thurstone's distance scale which is known in psychometrics. Experiments were performed with the two kinds of the filtering distortion systems, low pass and high pass, and with the two kinds of non-linear distortion, 2nd and 3rd harmonic, systems. The results of these experiments were compared form the view point of the naturalness by means of the common distance scale.
