A new hybrid active noise control system with residual error separation structure

The conventional broadband active noise control (ANC) system may not be able to function well when the target noise contains both wideband and narrowband components simultaneously. Feed-forward hybrid active control has attracted quite a lot attention recently, as it can effectively suppress both components at the same time. Such hybrid ANC system consists of three tightly integrated subsystems, namely, the sinusoidal noise canceller (SNC), broadband ANC (BANC) system and narrowband ANC (NANC). The BANC and NANC subsystems are placed in a parallel form, such that a good performance can be achieved. What\´s more, the update formulas of the two subsystems depend on the overall residual noise of the whole system, which is a combined measurement of two individual errors that correspond to the wideband and narrowband noise reduction, respectively. Using this "global" residual error may make both subsystems unable to reach their best performance. In this paper, a new hybrid ANC system is proposed to tackle this problem, by adding a new residual error separation (RES) subsystem to the conventional hybrid ANC system such that the two subsystems can update themselves based on their own residual errors. In this way, the two subsystems can work more effectively and make the whole system more capable. Extensive simulations show that the new system enjoys improved performance.