Principle and application of adaptive noise equalizer

This paper presents the principle and application of an adaptive noise equalizer (ANE) with adjustable gain or attenuation capabilities. The residual error of the ANE system contains the narrow-band noise components whose amplitude can be linearly and arbitrarily controlled by adjusting the gain parameter of the equalizer. Each ANE consists of a sinusoidal reference input and two adaptive weights. A pseudo error minimum method is developed to effectively utilize the well-understood least-mean-square algorithm. By partially separating the system output from the cost function to be minimized, the ANE can perform either a harmonic noise attenuator or amplifier by a predetermined amount. The application to active noise control is presented, and computer simulation results demonstrate the desired noise shaping capability