Digital services in the ANIK C Earth Stations

The Digital Services in the ANIK C Earth Stations built for Telesat Canada are examined, with emphasis on the major requirements, design considerations, and the achieved performance. It is noted that a design compromise is required to optimize linear and nonlinear distortions, spectral regrowth interfering with the adjacent channels, and high-power amplifier output, since the operating bit error rate of the link depends on these parameters. The requirements related to this design compromise are reviewed, as are the long- and short-term stability problems arising from the frequency conversion processes. Some features of the system hardware are described with particular reference to digital terminal equipment filters and the carrier recovery circuit.