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Remote Active Noise Control

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Remote Active Noise Control

  1. 1. Remote FxLMS Algorithm for Active Control of Sound in Remote Locations Iman Ardekani Department of Computing Unitec Institute of Technology Auckland, New Zealand Waleed Abdulla ECE Department The University of AUckland Auckland, New Zealand APSIPA ASC 2014 APSIPA Annual Summit and Conference Cambodia, Dec. 9 – 12, 2014
  2. 2. Outline • ANC • ANC Analysis in Acoustic Domain • Remote ANC • Adaptive Remote ANC Algorithm • Results • Conclusion 2 2
  3. 3. Active Noise Control – Why? 𝜆 𝜆 = 𝑐 𝑓 wave length (m) sound velocity (m/s) frequency (Hz) 𝑑 effective passive control 𝑑 ≫ 𝜆 𝑓 (𝐻𝑧) 𝜆 (𝑚) 10000 0.0343 1000 0.343 100 3.343 Passive noise control is bulky and costly for low frequencies! 3
  4. 4. Active Noise Control – Original Idea 4 Primary Noise Secondary Noise Residual noise
  5. 5. Active Noise Control – Acoustic Domain 5 u(n) : original noise d(n) : primary noise Reference mic Error mic d’(n) : secondary noise v(n) : anti noise d(n)  u(n) d’(n) v(n) e(n) u(n) v(n) e(n) Control System Control System
  6. 6. Active Noise Control – Digital Electronic Domain 6 W Gu(n) e(n) FxLMS H v(n) Control System d(n) d'(n) Minimization of e(n) power through producing v(n) using u(n) and e(n) FxLMS Algorithm
  7. 7. Active Noise Control – Research Gap 7 𝜆 20 Traditional ANC e(n) Problems: - very small zone of quiet - space occupied by the error mic 10 dB ZoQ 𝜆 20 e(n) 10 dB ZoQ Advantage: - effective use of space in quiet zone Remote ANC (proposed)
  8. 8. ANC Analysis in Acoustic Domain – Coordinate System 8 u(n) Reference mic v(n) L1 e(n) Control Source L2 Lo Error mic (ZoQ centre) W G e(n) FxLMS Update Eq H + v(n) Digital control domain Physical domain z-axis L1 L0 L2 is
  9. 9. ANC Analysis in Acoustic Domain – Propagation 9 L1 z-axis y-axisϕ 1 d D L1 L2L0 z-axis y-axisϕ 1 d D L1 L2L0 ϕr Lr ϕr u(n) v(n) W Gu(n) e(n) FxLMS H + v(n) Digital control domain Physical domain
  10. 10. Remote Active Noise Control 10 Remote location D L1 z-axis y-axisϕ 1 d D L1 L2L0 ϕr Lr ϕr
  11. 11. Remote Active Noise Control 11 L1 z-axis y-axisϕ 1 d D L1 L2L0 z-axis y-axisϕ 1 d D L1 L2L0 ϕr Lr ϕr
  12. 12. Remote Active Noise Control 12 L1 L0 L2 z-axis y-axisϕ 1 d D L1 L2L0 z-axis y-axisϕ 1 d D L2L0 ϕr Lr ϕr y-axisϕ 1 d D L1 L2L0 z-axis y-axisϕ 1 d D L1 L2L0 ϕr Lr ϕr Traditional ANC Remote ANC
  13. 13. Remote Active Noise Control 13 Traditional ANC Remote ANC W Gu(n) e(n) FxLMS H + v(n) Digital control domain Physical domain z-axis L1 L0 L2 z-axis Krz Gu(n) e(n) Remote FxLMS H v(n) W a(n) -ϕr Digital control domain + Physical domain
  14. 14. Remote Active Noise Control 14 Traditional ANC Remote ANC W Gu(n) e(n) FxLMS H + v(n) Digital control domain Physical domain z-axis L1 L0 L2 z-axis Krz Gu(n) e(n) Remote FxLMS H v(n) W a(n) -ϕr Digital control domain + Physical domain
  15. 15. Results Page 15 r z-axis y-axis70o 0.5m L1 L2L0 Lr 10 20 30 40 50 60 −0.5 0 0.5 1 n f1 (n) 0 10 20 30 40 50 60 −0.5 0 0.5 1 n f2 (n)
  16. 16. Results Page 16
  17. 17. Results Page 17
  18. 18. Conclusion • A novel model for the analysis of the ANC systems in the acoustic domain is proposed. • Based on this model, a methodology for active noise control in remote location is developed. • An adaptive framework for the realization of the proposed remote ANC system is developed. • Using remote ANC idea, the space available in the quiet zone can be used more effectively. • Future work: targeting 3D zones of quiet in remote locations instead of a point. Page 18 𝜆 20 e(n) 10 dB ZoQ

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