Author(s)

G. Rosenhouse

Abstract

The paper reviews techniques of active noise and vibration cancellation. Early developments and recent advances are surveyed including the theoretical background. Some of the old and a myriad of new applications are referred to in the text. 1 Introduction In general, the principle of active noise and vibration attenuation does not change, whatever system it is applied to. This principle postulates that when opposite noise and vibration fields are equal to the original ones, but in "anti phase", the two sounds will cancel each other by "destructive interference ".An anti-noise or-vibration is usually transmitted by a loudspeaker or a vibration transducer to the protected area in order to cancel there the existing unwanted noise/vibration. On the other hand, sounds to be heard, like speech, are subtracted from the canceled noise. These wanted soun

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