Patent ID: 6879922

Claim:
A method for providing a corrective modulation signal to suppress an acoustic pressure wave in an operational system, the method comprising the steps of: sampling the acoustic pressure wave generated in the operational system; sampling a previously generated corrective modulation signal, the previously generated corrective modulation signal having parameters; performing fast Fourier transform processing on the sampled acoustic pressure wave; performing a pair of single frequency discrete Fourier transform processing on the sampled acoustic pressure wave; determining the frequency, phase and magnitude of a dominate pressure wave in the acoustic pressure wave based on the fast Fourier transform processing and the discrete Fourier transform processing; and generating a sinusoidal corrective modulation signal to suppress the acoustic pressure wave based on the frequency, phase and magnitude of the dominate pressure wave and the parameters of the previously generated corrective modulation signal, the corrective modulation signal being at substantially the same frequency as, and generally 180 degrees out of phase with, the acoustic pressure wave.