ACOUSTIC NOISE CANCELLATION USING ADAPTIVE FILTERING

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Abstract
All the physical systems when they operate produce physical noise, which is a mixing of an infinitive number of sinusoidal harmonics with different frequencies. So, the initial signal information is corrupted with this noise. This complex signal, may be very noisy, so much that the human ear or other system which may follow it, cannot receive correct the initial signal.

2. Literature Survey
Some of the earliest works in adaptive interference cancelling was performed by Howells and Applebaum and their colleagues at the General Electric Company between 1957 and1960. They designed a built a system for antenna side lobe cancelling using a reference input derived from an auxiliary antenna and a simple two-weight adaptive filter [1].


3.2 Adaptive filters
An adaptive filter is a filter that self-adjusts its transfer function according to an optimization algorithm driven by an error signal. Because of the complexity of the optimization algorithms, most adaptive filters are digital filters. By way of contrast, a non-adaptive filter has a static transfer function. The adaptive filter uses feedback in the form of an error signal to refine its transfer function to match the changing parameters.