The first adaptive filter is used as a preconditioning stage so that its output signal has the requisite correlation property and high SNR (signal-to-noise ratio) to make the second adaptive filter more effective.

• 第一级自适应滤波器作为预处理级，使信号获得较好的相关性和信噪比，确保第二级自适应滤波器获得更优的性能。