Active noise control systems for periodic noise signals

This work presents an active noise control (ANC) system for periodic noise signals. Conventional feedforward ANC systems can reduce periodic noise by an adaptive filter excited by a merged reference signal, which is the summation of multiple sinusoidals corresponding to the harmonic frequencies of undesired noise. This work uses a frequency separation system to split error signal into several sets. Each set of error signal has the same frequency harmonics with its reference signal. So, the adaptation of weights by filtered-X least mean square (FXLMS) algorithm only processes the signals with same frequency components. A new performance index is also given. Computer simulations for periodic noise cancellation are conducted in this paper to prove the enhancement.