Feed Forward Active Noise Control System with Secondary Path Modelling Technique Using New Adaptive Step Size Based Wavelet Denoise

In the feed forward Active Noise Control system (ANC) with secondary path modelling there are two important requirements to be satisfied. The first is that an accurate estimate of ) (z S should be produced, regardless of the controller transfer function ) (z W . This independence property will ensure that the overall ANC system is robust. The second requirement is that the adaptive filter ) ( ˆ z S should not intrude on the operation of the ANC system. These two properties appear to be mutually exclusive, because in order to obtain an accurate and independent estimation of ) (z S it would be preferable for the modelling filter ) ( ˆ z S to manipulate the excitation (secondary) signal ) (n y directly. However, for the ) ( ˆ z S to be unobtrusive, it should observe only the signals already in the system. Consequently, in a practical ANC system, a tradeoff between independence and intrusion has to be resolved.