Measurements Mobile station Mobile station Figure 61.37 Comparison between conventional and GSM measurement set up for transmission 61/32 Telecommunication system measurements computer e.g. Ethernet R.F. and signalling Controller test set Digital a.f. Mobile station Electrical man-machine interface Figure 61.38 Configuration of a text set for r/f/. signalling and digital audio measurements on GSM mobiles as far as real time characteristics and signalling facilities are con- HP (1991a) Standard and CRC-4 Frame Testing, Application Note cerned. 1221-1, Hewlett-Packard Publication No. 5091-2070E. As part of the network infrastructure, the base station is linked up HP (1991b) Testing N x 64 kbit/s Services, Application Note 1211- with other network components via well defined interfaces. When 2, Hewlett-Packard Publication No. 5091-2069E. tests are carried out using a simulated mobile station, it is assumed HP (1991c) Testing Sub-rate Data Services (X.50, X.58), Applica- that these network interfaces are functioning correctly, or can be tion Note 1211-3, Hewlett-Packard Publication No. 1211-3, simulated by appropriate test signals. This is because the base Hewlett-Packard Publication No. 5091-2072E. stations exhibit transparent behaviour in many cases, for example, are not able to support the protocols of the r.f. interfaces themselves. HP (1992a) Introduction to SDH, Hewlett-Packard Publication No. 5091-3935E. HP (1992b) Introduction to SONET, Hewlett-Packard Publication No. 5091-3936E. 61.15 References Luttich, F. Klier, J. (1989) Signal generators SMGU and SMHU - nothing but the best, News from Rohde & Schwarz, No. 126. HP (1990) High Productivity Measurements in Digital Trans- Maucksch, T. (1990) GSM test set CMTA94 for the European mission, Application Note 387, Hewlett-Packard Publication digital mobile radio network, News from Rohde & Schwarz, No. No. 5959-7898. 129 pp. 4-7. Speech Channel Transmitter coder coder Signalling Speech Channel Receiver decoder decoder Signalling Figure 61.39 Internal interfaces of 