FPGA Implementation of Embedded Communication System

A modem modulates outgoing digital signals from a computer or other digital device to analog signals and demodulates the incoming analog signal and converts it to a digital signal for the digital device. Almost all the modems implemented on field programmable gate array (FPGA) concentrate only on the modulation and demodulation part. They do not take into account the processes involved before modulation at the transmitting end and the processes involved after the demodulation at the receiving end. This paper aims at implementing and testing a programmable modulation scheme using SpartanXC3S500E FPGA. The modulation scheme adopted in this paper/work is quadrature phase shift keying (QPSK). A modem is implemented on the FPGA to test the modulation scheme and a reduced instruction set computing processor (RISC) is used to program the modem. The feature of this implementation is the realization of a complete communication system which considers all the features right from packet formation to modulation at the transmitting end to the recovery and error free reconstruction of the transmitted message at the receiving end.