Results of the 60 Mbit/s TDMA system. Tests via Symphonie

Within the framework of the Symphonie project, TDMA system tests were performed between the Symphonie ground stations of Pleumeur-Bodou in France and Raisting in Germany. The TDMA terminals used for these field trials were developed according to 60 Mbit/sec TDMA Intelsat specifications. The main features of this TDMA system are briefly described and the design of the terminals is presented. The tests and the results obtained are discussed. Specific functions of the TDMA technique, such as initial acquisition fast reentry, reference station replacement, and burst position control were tested successfully under normal service conditions. The same tests were repeated under more severe conditions obtained by artificial degradation of the transmission channel or by addition of a co-channel interference circuit. These tests show that the service is still possible even under extreme conditions, i.e., bit error rate of 0.001. These tests demonstrate that this transmission system can work successfully by satellite and are of great value to the development of operational TDMA systems.