METHOD FOR ACTIVE SUPPRESSION OF ACOUSTIC NOISE Russian patent published in 2009 - IPC G10K11/178 

FIELD: physics, acoustics.

SUBSTANCE: invention is related to facilities for protection against acoustic noise caused by operating ventilation systems in residential premises and in moving objects. Method includes excitation of additional noise fields, in which signals for excitation of additional fields with the help of negative feedback chain with application of acoustic field exciter, acoustic pressure receiver, chain of preliminary amplifier control and generator of control voltage. Besides preliminary amplifier amplification ratio is varied by supply of additional pressure receiver signal to control voltage generator input, with time of main pressure output signal advance, which satisfies the following condition: T_AD≥3τ_c, T_AD=L/c, where: T_AD - value of output signal advance, τ_c - time constant of preliminary amplifier control circuit.

EFFECT: higher efficiency of noise suppression and operation stability under unstable acoustic conditions.

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