Resumen
It consists of a control system developed on a signal processing card DSP, which generates electrical signals that are amplified and converted into acoustic pressure waves by a loudspeaker and are superimposed in opposite phase with the pressure waves of the noise, producing an attenuation of same. The controller, based on an adaptive genetic algorithm, only attenuates the type of noise that is gathered by a sensor (microphone) and optimises its functioning as a function of the electric signal gathered by another microphone situated in the acoustic cancellation zone. The system produces acoustic attenuations greater than 25 decibels for periodic low- frequency noise (60 to 500 hertz), whether of fixed or variable frequency. <IMAGE>