Abstract
This paper analyzes narrowband active noise and vibration control (ANVC) systems using multiple second-order adaptive filters configured in parallel form with the filtered-x least mean square algorithm. Theoretical analysis of convergence of the algorithm is based on the autocorrelation and crosscorrelation matrices of the overall parallel structure. Analysis results show that extra harmonics are induced in the residual error because of using a single error signal to update all adaptive filters with different sinusoidal reference signals. An optimized filter-adapting method which uses bandpass filters to split the error signal into multiple bandlimited error signals according to frequencies of reference signals is proposed to improve the performance of narrowband ANVC systems in steady state. Computer simulations are conducted to verify analysis results and performance of the optimized narrowband ANVC system.