HD-SAT modems for the satellite broadcasting in the 20 GHz frequency band

This paper introduces the HD-SAT project and describes the two satellite modems designed for high definition digital television broadcasting by satellite in the 20 GHz frequency band. The graceful degradation satellite modem uses layered modulation (TCM-8PSK/QPSK) to increase service continuity in this rain-attenuation sensitive band. The 45-70 Mb/s TCM-8PSK modem demonstrates the feasibility of domestic variable rate receivers by using digital demodulation techniques suitable for very highly integrated implementations. Together these modems, both of which have been the subject of prototype demonstration and tests, address the essential functional and implementation issues of the Ka band for digital HDTV broadcasting.