Acoustic feedback neutralization in active noise control systems

Abstract

This letter proposes a method for active noise control (ANC) systems with online acoustic feedback neutralization. The proposed method is a modified version of authors' previous work, and the objective here is to reduce the computational complexity. This is achieved by combining the role of feedback path modeling and neutralization filters. The computer simulations are carried out which demonstrate that the proposed method achieves better performance than the existing methods and at somewhat reduced computational cost.

Variable step-size based method for acoustic feedback modeling and neutralization in active noise control systems

“…This section presents the simulation experiments performed to verify the effectiveness of the proposed method in comparison to Kuo's method [14], and previous method [16,23]. The performance comparison is carried out on the basis of following performance measures:…”

“…Hence a small step size is used initially, and later its value is increased accordingly. Computer simulations demonstrate the improved performance of the proposed method, which is achieved at a little increased computational cost as compared with the previous method [16].…”

“…In these two methods [14,15], two filters are used for b F ðzÞ: adaptive for FBPM and fixed for FBN. By combining these two task of modeling and neutralization in one adaptive filter, as feedback path modeling and neutralization (FBPMN) filter, a simplified method is proposed in [16], and is shown in Fig. 3.…”

“…3. As in existing methods [13][14][15][16], a low-level random noise signal v(n), uncorrelated with the reference signal x(n) is added with the output y(n) of W(z).…”

“…We see that the previous method requires L f fewer multiplications per iteration as compared with Kuo's method. The structure of the proposed method is same as that of the previous method, except for the computation of variable step-size parameter as described earlier, and hence requires a few more computations per iteration as compared to previous method [16,23], yet the computational cost is somewhat lower as compared to Kuo's method [14]. This saving in computational cost is advantageous in practical ANC systems which may require more than two loudspeakers and error microphones to cover an appreciable area, and the impulse response of actual acoustic paths may be very long requiring long adaptive filters.…”