基于自适应对消的收发隔离技术

Transmitter-Receiver Isolation Technology Based on Adaptive Noise Cancellation

收发隔离问题是机载干扰机的关键问题,固定步长的LMS算法由于跟踪性能不佳,应用在时变环境下基于自适应对消的收发隔离中隔离性能不好。针对此问题,提出了一种基于瞬时比值因子的变步长NLMS算法,该算法利用瞬时比值因子的指数函数形式,自适应调整步长因子,增强了算法跟踪性能。理论分析和仿真证明:时变耦合环境下,基于该变步长NLMS算法的收发隔离性能较文献有较大改善。

Transmitter-receiver isolation is an important problem in airborne jamming system.Isolation performance of adaptive noise cancellation based on fixed step size LMS algorithm is low for the worse convergence accuracy. For this problem,a variable step size NLMS algorithm based on the instantaneous ratio factor is proposed in this paper. Exponential function forms of the instantaneous ratio factor are employed in this variable step size NLMS algorithm to adjust the step size adaptively and the convergence rate and convergence accuracy is improved obviously. The theory analysis and simulation results demonstrate that the isolation performance based on the proposed algorithm is better than that based on other LMS algorithms under time varying environment.