Frequency domain simultaneous equations method for active noise control systems

This paper presents a new method applied to feedfoward type active noise control systems. This method, named frequency domain simultaneous equations method, is based on a different principle from the filtered-x algorithm requiring a filter modelled on a secondary path from a loudspeaker to an error microphone. Instead of the filter, this method uses an auxiliary filter identifying the overall path consisting of a primary path, a noise control filter and the secondary path. This paper first presents a computer simulation result demonstrating that the convergence speed of the proposed method is much higher than that of the filtered-x algorithm, and finally, by using an experimental system, verifies that the proposed method can automatically recover the noise reduction effect degraded by path changes.