Design of digital IIR filter: A research survey

Performance analysis of a diffusion control method for ANC systems and the network design

Active noise control system has been actively researched over the past half century, and implemented to reduce noises in ducts, headsets, and inside several automobile models. However, active control of noise fields, and specifically broadband noise fields, in rooms is still a barely explored topic due to the difficult of obtaining the reference signals, the challenge of online secondary path estimation, and the causal control constraint. In this paper, an active noise control system is developed that can cancel outgoing broadband noise fields in rooms. The proposed system decomposes the noise field on a sphere surrounding the noise sources into spherical harmonic modes, exploiting their directionality to generate the reference signals and remove the need for online secondary path estimation. A time-domain sound field separation algorithm and a time-wave domain adaptive algorithm allow the proposed system to meet the causal control constraint. Simulation results demonstrate that the proposed system can cancel broadband noise field globally in a room without suffering from the secondary source feedback problem.

Active Control of Outgoing Broadband Noise Fields in Rooms

The installation of remotely-operated service robots in the environments of our daily life (including offices, homes, and hospitals) can improve work-from-home policies and enhance the quality of t...

https://www.tandfonline.com/doi/pdf/10.1080/01691864.2021.1928552

Semiotically adaptive cognition: toward the realization of remotely-operated service robots for the new normal symbiotic society

Time-division multiple reference approach for multiple-channel active noise control system

Multichannel feedforward active noise control system combined with noise source separation by microphone arrays

In this paper, we propose a multichannel active noise control (ANC) system with an optimal reference microphone selector based on the time difference of arrival (TDOA). A multichannel feedforward ANC system using upstream reference signals can reduce various noises such as broadband noise by arranging reference microphones close to noise sources. However, the noise reduction performance of an ANC system degrades when the noise environment changes, such as the arrival direction. This is because some reference microphones do not satisfy the causality constraint that the unwanted noise propagates to the control point faster than the anti-noise used to cancel the unwanted noise. To solve this problem, we propose a multichannel ANC system with an optimal reference microphone selector. This selector chooses the reference microphones that satisfy the causality constraint based on the TDOA. Some experimental results demonstrate that the proposed system can choose the optimal reference microphones and effectively reduce unwanted acoustic noise.

https://www.mdpi.com/2076-3417/8/11/2291/pdf

Multichannel Feedforward Active Noise Control System with Optimal Reference Microphone SelectorBased on Time Difference of Arrival

In this paper, we propose a 3rd-order nonlinear IIR filter for compensating for nonlinear distortions of loudspeaker systems. The 2nd-order nonlinear IIR filter based on the Mirror filter is used for reducing nonlinear distortions of loudspeaker systems. However, the 2nd-order nonlinear IIR filter cannot reduce nonlinear distortions at high frequencies because it does not include the nonlinearity of the self-inductance of loudspeaker systems. On the other hand, the proposed filter includes the effect of such self-inductance and thus can reduce nonlinear distortions at high frequencies. Experimental results demonstrate that the proposed filter can realize a reduction by 4 dB more than the conventional filter on intermodulation distortions at high frequencies.

Kenta Iwai

Papers

Multichannel feedforward active noise control system combined with noise source separation by microphone arrays

Multichannel Feedforward Active Noise Control System with Optimal Reference Microphone SelectorBased on Time Difference of Arrival

Linearization of dynamic loudspeaker system using third-order nonlinear IIR filter

Third-Order Nonlinear IIR Filter for Compensating Nonlinear Distortions of Loudspeaker Systems

Analysis of derivative of instantaneous frequency and its application to voice activity detection