An active noise control system based on simultaneous equations method without auxiliary filters

A simultaneous equations method gives an active noise control algorithm without estimating an error path. This algorithm requires the identification of a transfer function from a reference microphone to an error microphone containing the effect of a noise control filter. It is achieved by the system identification of an auxiliary filter. As a result, the amount of computation is increased. A new simultaneous equations method without the identification of the auxiliary filter is proposed. By storing a small part of an input signal and an error signal, we avoid this identification. Therefore, the amount of computation can be reduced by approximately 25% and the same noise reduction performance as with an ordinary method is obtained. From simulation examples, it is verified that the merits of the ordinary method are retained in the proposed method.