| 摘要 |
A telecommunications testing apparatus comprises a signal generator (7) which generates a speech-like synthetic signal, which is supplied to the input of a telecommunication apparatus (1) to be tested. The distorted output of the telecommunications apparatus (1) is supplied to an analysis used (8), which derives, for both the undistorted test signal and the distorted signal from the telecommunications apparatus (1), a measure of the excitation of the human auditory system generated by both signals, taking into account both spectral masking and temporal masking phenomena. The difference between the two excitations is then calculated, and a measure of the loudness of the difference, and the statistical distribution of this loudness over pitch and time, is derived which is found to indicate to a high degree of accuracy the human subjective response to the distortion introduced by the telecommunications system. |
