Adaptive digital techniques for audio noise cancellation

Discusses two adaptive digital techniques for audio noise cancellation. The first technique, adaptive predictive deconvolution, uses an adaptive linear predictor to estimate and cancel (time) correlated noise components on an audio signal. The second technique, adaptive filtering, employs two audio signal inputs, the first having the desired audio signal along with noise and the second sensing principally the noise. The second, noise signal is adaptively filtered and subtracted from the first signal cancelling noise components common to the two inputs. A stand-alone digital signal processor has been developed to carry out these two noise cancellation techniques. This automatic digital audio processor, ADAP, carries out these processes in real time with up to a 256th order digital filter.