Abstract: For the automatic evaluation of the transmission quality of a voice signal that is transmitted by a digital transmission system (1) frequency components that correspond to a data frame rate (fr) of the digital transmission system (1) are extracted from the received voice signal and analyzed. In order to obtain a measurement value that is independent of signal strength, a standardization with the spectral output values occurring in the middle of the quoted frequencies can be conducted. For comparison purposes, an undistorted voice signal is processed the same way in advance. The measurement values of the transmitted voice signal are placed at a ratio to the reference values and then evaluated, e.g., by a neuronal network (13).

Abstract: A method and device for checking a telecommunication system (4) with respect to an accurate routine detection of system-internal call data records (13, 14). Various communications connections are established and later terminated between two subscriber stations (2,3) via the telecommunication system (4) on the basis of predefined communication parameters; further call data records (10a,10b) are independently prepared and saved from these communications connections at both of these subscriber stations (2,3); and the system-internal call data records (101013) for said communications connections that are routinely created by the telecommunications system (4) itself, are compared to the further call data records (10a, 10b).

Abstract: A recorded voice test signal is transmitted from a transmitting end of a mobile communication system, and in a test unit at the receiving end a frame generator is synchronized with the received signal. Each frame of the signal is evaluated in computing circuits on the outputs of the frame generator, which calculate characteristic values of each frame which are then subtracted from calculated characteristic reference values of the frames stored in a memory. The differences between these characteristic values are fed to a neural network which classifies the quality of the difference signals as Good, Medium and Bad, and a defuzzyfication logic circuit further refines the quality classification output, whereby the transmission quality throughout the mobile communication system can be reprodicbly rated for a system quality rating.