Simulation of LMS based adaptive noise cancellation using Labview

The audio signals processed in the signal measurement systems are inevitably susceptible to unwanted noise which significantly affects the quality of the signal and the overall performance of the signal communication systems. Due to its' random and unpredictable nature, the amount of noise in signals has proven to be a significant issue in designing these systems and recently has been a trending research topic. In this regard, the active noise cancellation method has proven to be an effective technique for eliminating the noise effects on signal processing. The concept of active noise cancellation is based on the application of adaptive filters and algorithms proposed to reduce the signal corruption and distortion caused by the noise due to the principle of destructive interference. In this paper a simulation model of active noise reduction technique using the LMS (Least Mean Square) algorithm in Labview is presented. The purpose of the work is to investigate the noise cancellation effect on a recorded audio file in terms of analyzing the audio file before and after filtering out the noise by using the LMS algorithm and discuss the results thereof.

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Reduced complexity diffusion filtered x least mean square algorithm for distributed active noise cancellation

Signal Image and Video Processing ◽

10.1007/s11760-018-01412-1 ◽

2019 ◽

Vol 13 (3) ◽

pp. 447-455

Author(s):

Ruchi Kukde ◽

M. Sabarimalai Manikandan ◽

Ganapati Panda

Keyword(s):

Noise Cancellation ◽

Mean Square ◽

Least Mean Square ◽

Active Noise Cancellation ◽

Active Noise ◽

Least Mean Square Algorithm ◽

Reduced Complexity

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Experimental investigation on the potential of the Feedback Fx-LMS Active Noise Control technology for use in industrial generator sets

E3S Web of Conferences ◽

10.1051/e3sconf/202131208007 ◽

2021 ◽

Vol 312 ◽

pp. 08007

Author(s):

Marco Ciampolini ◽

Lorenzo Bosi ◽

Luca Romani ◽

Andrea Toniutti ◽

Matteo Giglioli ◽

...

Keyword(s):

Acoustic Waves ◽

Noise Control ◽

Noise Source ◽

Acoustic Noise ◽

Active Noise Control ◽

Lms Algorithm ◽

Destructive Interference ◽

Exhaust Pipe ◽

Least Mean Square ◽

Active Noise

Active Noise Control (ANC) has been considered a promising technology for the abatement of acoustic noise from the mid-20th century. Feedback and Feedforward ANC algorithms, based on the destructive interference principle applied to acoustic waves, have been developed for different applications, depending on the spectrum of the noise source. Feedback ANC algorithms make use of a single control microphone to measure an error signal which is then employed by an adaptive filter to estimate the noise source and generate an opposite-phase control signal. The Fx-LMS (Filtered-X Least Mean Square) algorithm is mostly adopted to update the filter. Feedback ANC systems have proven to be effective for the abatement of low-frequency quasi-steady noises; however, different challenges must be overcome to realize an effective and durable system for high-temperature application. This paper aims at experimentally assessing the feasibility of a Feedback Fx-LMS ANC system with off-line Secondary Path estimation to be used in mid-size diesel gensets for the reduction of the exhaust noise. Several solutions are proposed, including the mechanical design, the development of the Fx-LMS algorithm in the LabVIEW FPGA programming language, and the key features required to prevent parts from thermal damage and fouling. The developed prototype was implemented on a 50-kW diesel genset and tested in a semi-anechoic chamber. The noise abatement inside the exhaust pipe and at different measurement points around the machine was evaluated and discussed, showing good potential for improving the acoustic comfort of genset users.

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Semi-adaptive active noise cancellation headphones

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-2808 ◽

2021 ◽

Vol 263 (2) ◽

pp. 4717-4723

Author(s):

Song Li ◽

Roman Schlieper ◽

Jürgen Peissig

Keyword(s):

Ambient Noise ◽

Adaptive Filters ◽

Sudden Change ◽

Dynamic Environments ◽

Noise Cancellation ◽

Noise Attenuation ◽

Estimation Errors ◽

Active Noise Cancellation ◽

Active Noise ◽

Relative Weighting

Active noise cancellation (ANC) headphones are becoming increasingly important as they can effectively attenuate perceived ambient noise. Fixed filters are commonly applied in commercially available ANC headphones due to their robustness. However, they are not capable of adapting to changes that occur in dynamic environments, resulting in degraded ANC performance. In contrast, adaptive filters are able to update the ANC filters to compensate for noise in dynamic environments, but large estimation errors can occur due to a sudden change in direction/type of noise or secondary path. Some studies have suggested an ANC system by combining fixed and adaptive filters. Based on this mechanism, we propose a semi-adaptive ANC system in which the fixed and adaptive filters are weighted in real-time. Initially, the weighting for the fixed filter dominates the whole system to ensure the robustness of the ANC system. Then, the residual error provided by the adaptive filter is simulated and compared to the real measured one to determine the relative weighting between the fixed and adaptive filters. In this study, this approach is applied to a feedback ANC system. Simulation results show that our proposed approach achieves high noise attenuation performance while maintaining robustness with time-varying secondary paths.

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