Abstract
This invention proposes two novel active noise control techniques by using the feedforward H2 and H∞ optimal model matching principle. These methods effectively overcome theproblem of inverse plant resulted from the inherent nonminimum phase property of the cancellation path. The proposed algorithms are implemented by using the digital signal processor. The experimental results obtained by using the H2 and H∞ feedforward techniques show comparable attenuation for stationary noises in a duct as conventional methods. The proposed methods also have potential in suppressing transient noises that have been the major difficulty to the adaptive methods. The active electrical muffler exhibits effectiveness in suppressing exhaust noise from gasoline engine ,the noise from a blower and the impact noise from a forge hammer.