Analysis of adaptive interference cancellation system with limiter

The interference cancellation ratio (ICR) is influenced by the zero offsets of the devices in the weight branches. The gains in weight branches are moved to error feedback loop to guarantee ICR without influencing the convergence speed. The limiter is used to protect the multipliers thus the system becomes a nonlinear system. Through the describing function method and simulation, the stability, dynamic characteristics and steady-state characteristics are analyzed. With limiter, the stability of the system is uninfluenced. The steady-state characteristics are related with the parameters of limiter, the gain, the time constant of the low-pass and the amplitude of the signal. The convergence speed will decrease under the conditions of under damping and critical damping. If system is over-damped, the initial gain determines the growth of convergence speed. In this paper, a criterion to judge whether steady-state characteristics varies and the proper rule to increase the convergence speed with over damping are obtained.