Design of A Reconfigurable Digital Modulator For High Bit Rate Data Transmission

Satellites have become an important part of present-day data communication systems. They play a significant role in the development and advancement of technologies such as navigation, telemedicine, tele-education, weather forecasting, radio and TV broadcasting, defense etc. With more and more technologies depending on satellite technology, the need of the hour is a reliable high throughput communication system that minimizes on hardware, power and bandwidth requirements. In order to meet the constraints, an IQ modulator based reconfigurable digital modulator is proposed in this paper. The modulator is designed in such a way that it can support any of the M-PSK or N-QAM modulation scheme. Higher order modulations in conjunction with proper pre-modulation filtering of baseband data is shown to minimize the bandwidth requirements for high bit rate data applications. The approach also allows for dynamic reconfiguration of the system for different modulation schemes, data rates and spectral occupancy without effecting any changes to the hardware. The proposed system is predicted to be the forerunner for all future space-based high data transmitters.