Introduction of TDMA in the Intelsat system

A 120 Mbps Time Division Multiple Access system (TDMA) employing Digital Speech Interpolation (DSI) will be introduced into the Intelsat network on the Atlantic Major Path 2 satellite in 1983. The system is designed to operate with an 80 MHz hemispheric beam and zone beam coverage transponders at 6/4 GHz, and with spot beam transponders at 14/11 GHz (cross-strapped transponders at 14/4 and 6/11 GHz may also be used). Using four-phase coherent phase-shift keying, the entire bandwidth of the 80 MHz transponders is occupied. Each TDMA terminal can transmit up to 16 bursts and receive up to 32 bursts per frame for a frame length of 1 ms. Each DSI module can accomodate 240 terrestial channels on 127 satellite channels. By 1993, it is expected that 60 percent of the Atlantic region traffic will be conveyed through TDMA.