DESIGN AND APPLICATION OF THE RD-4A AND RD-6A 64 QAM DIGITAL RADIO SYSTEMS

摘要

The Northern Telecom RD-4A and RD-6A long haul digital radio systems operate in the North American 4 GHz and 6 GHz common carrier bands. The 64 QAM modulation scheme used provides the spectral efficiency to transmit two DS-3 rate signals in the 4 GHz band and three DS-3rate signals in the 6 GHz band while maintaining full compatibility with analog radio operating in the same frequency plans. This paper discusses the RD-4A and RD-6A system design considerations, key system performance parameters, details of system architecture and hardware design considerations. Measured data which verified that the system met all longhaul performance objectives is presented.