Image Rejection Research on Digital IF Quadrature Detector for Complex Band-pass Signal

Two kinds of definitions of image rejection ratio (IRR) for complex band-pass signal are put forward, and the signal processing flow for digital IF quadrature detector is discussed in this paper. Simulation results of different definitions of ERR for a sort of complex band-pass signal are presented, which employ Bessel interpolation approach, low-pass filtering approach, polyphase filtering approach and frequency domain approach, respectively. The analysis and simulation results indicate that the values of IRR of different definitions for the same IF quadrature detector approach differs from 5 to 15 dB, and excellent IRR can be obtained with frequency domain approach, which is a more ideal IF quadrature detection approaches at present