Electronic Journal Technical Acoustics ISSN 1819-2408

Allan Kim, Andrey Bykov, Andrey Troshin

Active noise cancellation: air conditioner and transformer case study

language: English

received 31.01.2005, published 23.02.2005

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ABSTRACT

Two cases of active noise cancellation technique are discussed in the paper. A feedforward control systems for both cases were used. FxLMS (Filtered Least Mean Square) algorithm for noise reduction of air conditioner is implemented whilst sub band LMS utilized in transformer case. To provide a good quality of the reference signal the special method of flow isolation for reference and error microphones is proposed. The noise reduction efficiency of 15 and 10 decibels at frequencies 90 and 240 Hz is provided using proposed configuration of the system. Three tonal components 120, 240 and 360 Hz are dominated in transformer noise spectrum. Implementation of sub band FxLMS algorithm for transformer case has shown the high efficiency of proposed technique within local area for tonal component 120 and 340 Hz. The most wide silent zone at frequency 240 Hz is revealed during study.

11 pages, 14 figures

Сitation: Allan Kim, Andrey Bykov, Andrey Troshin. Active noise cancellation: air conditioner and transformer case study. Electronic Journal “Technical Acoustics”, http://www.ejta.org, 2005, 7.

REFERENCES

1. Nelson P. A., Elliott S. J. Active control of sound. Academic press, 1992.
2. Colin H. Hansen. Understanding active noise cancellation. Spon Press, London and New York, 2001.
3. Scott D. Snyder Active Noise control Primer AIP Press Springer University of Adelaide 2000
4. Sen M. Kuo, Dennis R. Morgan. Active noise control: systems algorithms and DSP implementations. John Wiley and Sons Inc, 1996.
5. Connover W. B., Ringlee R. J. Recent contributions to transformer audible noise control. Transactions of the AIEE, Part III, Power Apparatus and Systems, vol. 74, 77–90.

		Allan Kim - Director of Acoustic solutions department at IT Magic. Co. Ltd. Seoul, Republic of Korea
		Andrey V. Bykov - Project leader and DSP programmer, Acoustic solutions department at IT Magic. Co. Ltd. Seoul, Republic of Korea
		Andrey G. Troshin - PhD, Acoustic expert and team leader, Acoustic solutions department at IT Magic. Co. Ltd. Seoul, Republic of Korea. e-mail: atroshin(at)yahoo.com