Bandwidth Efficient Baseband Multi-Modulator

The High Rate Baseband Multi-Modulator (HRBM) ASIC is being developed to provide High-Speed Bandwidth Effi- cient Modulations to NASA missions. Bandwidth efficiencies from 2.0 bits/symbol/Hz to 2.75 bits/symbol/Hz are selectable from three CCSDS modulations: Gaussian Minimum Shift Key- ing (GMSK), Filter Offset Quadrature Phase Shift Keying (Fil- tered-OQSK) and 8-Phase Shift Keying Trellis Coded Modula- tion (8-PSK TCM). An FPGA version of the HRBM is developed first to verify the individual modulation designs and character- ize timing and performance issues involved with digital base- band modulation synthesis. A Finite Input Response (FIR) filter is included to provided baseband pulse shaping to reduce out-of-band spectral emis- sions. This is filter is programmable and can be tailored to meet system requirements. The ASIC is targeted to provide up to 600 Mbps throughput and will provide serial as well as parallel in- put. This paper provides an overview of the technology devel- opment and current status.