Electronic Noise-Reducing System.
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
A method and apparatus for reducing noise from a near-field noise source present together with signals from a far-field source. The method uses an adaptive shaping filter and a summer, in conjunction with a directional reference sensor and a primary sensor which have at least a common sensing element there between. The directional reference sensor situated between the near-field noise source and the far-field signal source, rejects the broad-band signal but accepts the broad-band noise and feeds this noise into a reference channel of the adaptive filter. The primary sensor accepts both the far-field signal and near-field noise with equally sensitivity. The primary sensor feeds into the primary channel of the adaptive filter. The adaptive filter system subtracts the noise in the reference channel form the signal-plus-noise in the primary channel, thus producing an output having a greatly improved signal-to-noise ratio.