Single-sensor active noise cancellation

Active noise cancellation is an approach to noise reduction in which a secondary noise source that destructively interferes with the unwanted noise is introduced. In general, active noise cancellation systems rely on multiple sensors to measure the unwanted noise field and the effect of the cancellation. This paper develops an approach that utilizes a single sensor. The noise field is modeled as a stochastic process, and a time-adaptive algorithm is used to adaptively estimate the parameters of the process. Based on these parameter estimates, a canceling signal is generated. In general, the transfer function characteristics from the canceling source to the error sensor need to be accounted for. If these can be accurately measured in advance and are invertible except for the propagation delay between the source and sensor, then the essential problem becomes one of predicting future values of the noise field. The algorithm developed is evaluated with both artificially generated noise and with recordings of aircraft noise