Digital down-conversion design based on polyphase filtering structure

Digital down-conversion technology based on the structure of bandpass sampling is one of the key technologies of software radio receiving system. While the traditional digital mixing orthogonal demodulation using multiplier, to a certain extent, increase the computational complexity. This paper proposes a kind of digital down-conversion design based on polyphase filtering structure, effectively reducing the computational complexity. Firstly, conducting odd-even extraction and symbol correction; secondly, using time delay filter to update; Finally, outputing baseband signal after extracting. We use of software simulation to prove its feasibility.