Department of Electrical Engineering, Chung Yuan Christian University, Taoyuan 32023, Taiwan.
Sensors (Basel). 2020 Nov 23;20(22):6693. doi: 10.3390/s20226693.
Audio-integrated feedback active noise control (AFANC) systems deliver wideband audio signals and cancel low frequency narrowband noises simultaneously. The conventional AFANC system uses single-rate processing with fullband adaptive active noise control (ANC) filter for generating anti-noise signal and fullband audio cancelation filter for audio-interference cancelation. The conventional system requires a high sampling rate for audio processing. Thus, the fullband adaptive filters require long filter lengths, resulting in high computational complexity and impracticality in real-time system. This paper proposes a multirate AFANC system using decimated-band adaptive filters (DAFs) to decrease the required filter lengths. The decimated-band adaptive ANC filter is updated by the proposed decimated filtered-X least mean square (FXLMS) algorithm, and the decimated-band audio cancelation filter can be obtained by the proposed on-line and off-line decimated secondary-path modeling algorithms. The computational complexity can be decreased significantly in the proposed AFANC system with good enough noise reduction and fast convergence speed, which were verified in the analysis and computer simulations. The proposed AFANC system was implemented for an active headrest system, and the real-time performances were tested in real-time experiments.
音频集成反馈有源噪声控制（AFANC）系统可同时传输宽带音频信号并消除低频窄带噪声。传统的 AFANC 系统采用单速率处理，使用全带自适应有源噪声控制（ANC）滤波器生成抗噪声信号，使用全带音频消除滤波器进行音频干扰消除。传统系统对音频处理的要求采样率较高。因此，全带自适应滤波器需要较长的滤波器长度，导致计算复杂度高，实时系统不切实际。本文提出了一种多速率 AFANC 系统，使用抽取带自适应滤波器（DAFs）来减少所需的滤波器长度。抽取带自适应 ANC 滤波器由所提出的抽取滤波-X 最小均方（FXLMS）算法更新，抽取带音频消除滤波器可通过所提出的在线和离线抽取二次路径建模算法获得。所提出的 AFANC 系统的计算复杂度可以显著降低，同时具有足够好的降噪效果和快速收敛速度，这在分析和计算机仿真中得到了验证。该 AFANC 系统已应用于主动头枕系统，并在实时实验中进行了实时性能测试。
