New nonlinear adaptive FIR digital filter for broadband noise cancellation

The structure and the adaptive algorithm of a new nonlinear adaptive FIR digital filter. Called nonlinear delayed N-path adaptive FIR (NDNAFIR) digital filter, is presented for cancelling broadband noise from signals containing sharp edges. The filter structure is obtained by decomposing a FIR digital filter into N delayed parallel subfilters which facilitates high speed implementation. Adjustable bipolar sigmoid functions are placed at the output of each subfilter as well as after the summation of all subfilter outputs. Simulation results show that the ND-NAFIR digital filter outperforms those of the linear adaptive FIR digital filter and the nonlinear median filter in broadband noise cancellation in terms of convergence speed and average squared difference between original and recovered signals