Digital Costas loop design for coherent microsatellite transponders

This paper presents a design for a satellite transponder using a modified superheterodyne receiver, a digital Costas loop and a conventional transmitter. The overall architecture of the transponder is presented, along with detailed design information. The paper presents analyses of the receiver requirements, simulations of the digital Costas loop performance and a description of the transmitter. The effects of particular components and subsystems on critical transponder performance parameters are examined and evaluated. When necessary, specific mitigation paths are identified. The digital Costas loop design is presented and its performance is evaluated. Finally, the transmitter design is presented and its performance is evaluated. The paper concludes with a summary of the design.