14/11 GHz, 120 Mbit/s regenerative satellite transponder

This paper describes the design, implementation and performance of an experimental 14/11 GHz, 120 Mbit/s regenerative satellite transponder for possible use in the European communications satellite (ECS) system. Quarternary DPSK and CPSK are applied on the uplink and downlink, respectively. Demodulation and modulation are performed directly at RF. Specific components of the regenerative transponder, which are the pulse shaping filter, the differential demodulator, the baseband regenerator, the modulator and the output filter, were developed. Using the developed components, a laboratory model of the transponder was completed and evaluated. Bit-error-rate measurements were carried out with a test equipment simulating the earth terminals.