Realisation of controller transfer function for active noise cancellation
OwnerGraeme Colin Fullerinventor
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Abstract
An apparatus for realizing an active noise cancellation control law transfer function between a sensing microphone and a speaker. The apparatus includes a multiplicity of filters. Each filter is operable over a different frequency range. At least one filter has an adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realize a required control law transfer function. The adjustable parameter may in one embodiment be the amplitude. In other embodiments, it may be other parameters.
Claims10
Apparatus for realising an active noise cancellation control law transfer function between a sensing microphone and a speaker, the apparatus including a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realise a required control law transfer function.
A method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
- determining one or more acoustic or electro-acoustic characteristics of the apparatus, and;
- adjusting the adjustable parameter dependent on the characteristic such that the filters cumulatively realise a control law transfer function to implement active noise cancellation.
A method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
- sensing the noise cancellation performance of the apparatus, and;
- adjusting the adjustable parameter dependent on the sensed performance such that the filters cumulatively realise a control law transfer function to implement active noise cancellation.
Dependencies are inferred from the claim text.