Digital down-conversion design and implementation based on FPGA

Digital down-conversion technology is one of the most important technologies of software radio. This paper proposes a digital free mixing scheme of digital down conversion on the basis of digital mixing orthogonal demodulation, effectively reducing the computational complexity. Its working principle is clarified in this paper, mainly including free mixing, CIC filter and half-band filter. Finally, simple structure of the FPGA implementation scheme is presented to prove the designed feasibility through software emulation.