A new structure for nonlinear narrowband active noise control using Volterra filter

Many structures and algorithms have been developed for linear narrowband active noise control (NANC) systems, which are effective in suppressing sinusoidal noise generated by rotating machines and devices with reciprocating motion. However, the conventional linear NANC systems may seriously suffer from performance degradation due to the nonlinear distortions which, large or small, usually exist in real-life sound fields. Development of nonlinear NANC systems to solve the above-mentioned problems has recently attracted a great deal of attention and several structures and algorithms have been proposed based on the use of adaptive Volterra filter. In those systems, the sinusoidal noise at the reference point is distorted by the nonlinear part of a primary path, eventually adding some high-order harmonic components to the primary noise being targeted. But the main body of the primary noise is still dominated by linearity of the primary path. This paper presents a new structure for a nonlinear NANC system, where the largest portion of the primary noise power can be reduced by the conventional adaptive linear filter and the remaining portion due to high-order harmonics may be effectively suppressed by an adaptive Volterra filter. Numerical simulation results reveal that the proposed system is very effective in suppressing sinusoidal noise distorted by nonlinearity of the primary path.