Fixed-Point Design and Simulation of QPSK Based on FPGA
Hui Qian · Jisuanji fangzhen · 2009
Digital baseband signal can not be transmitted directly in some situation,so it should be modulated by carrier into appropriate frequency band signal.QPSK(Quaternary Phase Shift Keying) is one of the linear narrowband digital modulation technologies widely applied in mobile communication and satellite communication for its great performances such as high band utilization rate,good spectrum characteristic,effective anti-attenuation and available demodulation with noninterference.Using FPGA devices can integrate primary circuit board-level products into chip-level products,which can decrease power,improve reliability and edit the design online conveniently.In this paper,through studying the modulation technique of QPSK,top-down modularization design method,which partitions the entire QPSK modulation system into five small modules including series and conversion,difference encoding,decoding,CIC filter and orthogonal carrier modulation,is realized by Verilog hardware description language in FPGA modules.Digital signal transmission is implemented and finally the simulation result is verified by testbench.