Colloquium - Details

Master-Vortrag: Hybrid Approaches for Active Noise Cancellation in Headphones and Hearing Aids

Argyrios Kechagias
Mittwoch, 29. November 2017
11:15 Uhr
Hörsaal 4G

The presence of noise in today’s society is more prevalent compared to the past. With the advancement of technology, the traditional passive means of noise attenuation involving absorbing and repelling materials are assisted by devices performing active noise cancellation. This thesis is focused on noise cancellation applications for in-ear devices. Most available solutions on the market are implemented as fixed controllers. These have the advantage of reliable performance when operating in the conditions they were designed for, irrespective of the noise intensity. On the other hand, newer digital circuits have enabled the implementation of adaptive filters for the same purpose. These can attenuate the noise satisfactorily in different device positioning conditions however their performance depends on the noise
characteristics. The combination of those approaches, often referred to as hybrid design, limits their weaknesses and yields systems with a broader potential for noise attenuation. Here, various hybrid implementations are studied in terms of performance. Additionally, the most appropriate method for designing a fixed robust controller is chosen and used in the implementation of the evaluated systems. Moreover, the used adaptive filters are implemented with simple adaptive algorithms. Finally, a novel system, called the PCA-multicontroller is developed combining adapting filtering and the design of fixed controllers. Two alternative approaches for constructing the multicontroller are evaluated. The first design processes a set of secondary paths, while the second a set of specially designed controllers. The developed system is evaluated in the simulation.

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