Active noise cancellation system

Abstract

An active noise cancellation system, comprising a circuit for generating one or more reference signals (x(n)) proportional to the noise in the target area, several electronic circuits (1) having adjustable transfer functions (W), such as adaptive filters, adapted to receive the one or more reference signals (x(n)) and to generate noise cancellation signals (y(1,n)), sound sources (2) adapted to receive the noise cancellation signals (y(1,n)) and to generate cancellation noise in the target area for at least partial cancellation of the noise present therein, sensors (3) for detecting residual noise in the target area and converting it to electrical residual noise signals (e(m,n)), transmission path (4) having the estimated transfer function (C') of the transmission path between the electronic circuit (1) and the sensors (3) adapted to receive the one or more reference signals (x(n)), and tuning circuit (5) adapted to receive the residual noise signals (e(m,n)) and output signals from the transmission path circuit (4) and to generate tuning signals (w) and transmit them to the electronic circuit (1) for tuning the transfer functions (W) thereof, and second tuning circuit (6) adapted to receive both the cancellation noise signals (y(1,n)) and the residual noise signals (e(m,n)) and to generate second tuning signals (c) and transmit them to the transmission path circuit (4) for tuning the transfer functions (C') thereof.