초록 ▼

This invention concerns a method of, and apparatus for, reducing the ambient noise level at a location in the vicinity of a source of recurring noise. In its preferred embodiments the invention involves generating a series of cancelling noise signals which are exactly synchronized with the bursts of

This invention concerns a method of, and apparatus for, reducing the ambient noise level at a location in the vicinity of a source of recurring noise. In its preferred embodiments the invention involves generating a series of cancelling noise signals which are exactly synchronized with the bursts of recurring noise from the source and adapting the cancelling signals in the series on the basis of the success achieved in nulling the noise from the source at the location.

대표청구항 ▼

A method of reducing the amplitude of sound vibrations received at a selected location from a source of recurring noise, which method comprises the steps of: synchronizing by a timing signal from the source at said location a waveform generator and feeding to said location a secondary sound vibratio

A method of reducing the amplitude of sound vibrations received at a selected location from a source of recurring noise, which method comprises the steps of: synchronizing by a timing signal from the source at said location a waveform generator and feeding to said location a secondary sound vibration derived from an output waveform which at least partially nulls the sound vibrations at said location; thereafter storing in a memory component part waveforms of said output waveform and sequentially combining a series of said component part waveforms to modify the output waveform by a successive series of approximations while comparing the degree of cancellation of the unwanted sound vibration from the source at the selected location, each successive approximation being made by altering at least one of the individual component parts and adapting an alternation of a component part by updating that part in the memory or rejecting that part alternation on the basis of whether or not that part alternation improved the degree of cancellation of the unwanted sound vibration.