An improved digital quadrature frequency down-converter architecture

This paper describes an improved digital quadrature frequency downconverter architecture. The presented architecture implements the quadrature frequency downconversion as two successive angle rotations. First, a coarse angle rotation is performed by using a modified, low-latency CORDIC algorithm. Then, a fine angle rotation based on a simple trigonometric approximation is realized. Compared with solutions based on the conventional CORDIC algorithm, our architecture offers reduced tuning latency and smaller hardware cost. The use of the presented architecture is especially attractive for frequency agile communication systems.