Abstract: The frequency-domain and time-domain characteristics of adaptive interference cancellation system were analyzed, when interference signal had nonzero bandwidth. The nonzero bandwidth interference signal made the system a time-variation system. When the bandwidth was far less than the center frequency, the interference cancellation system could be approximated as an adaptive comb filter. The average convergence speed of the system was proportional to the overall reference signal gain, and the interference cancellation ratio (ICR) decreased with the increase of the bandwidth. The theoretical and simulation analyses of couple time delay matching reveal that the precise time delay matching can improve ICR significantly.