Method and apparatus for acoustic detection of a signal with a low signal-to-noise ratio, in the presence of a noise source

摘要

The system uses a local noise detector producing a reference signal for elimination from detected acoustic signals. The system for detecting acoustic signals in the presence of noise includes use of a vibration sensor (71) placed directly next to at least one source of parasitic noise (11). A signal is derived from this and used as a reference signal. A further signal is derived from an aerial (2) measuring acoustic pressure signals and this is correlated with the reference signal and fed to a processing unit (10). The support for the aerial comprises a dynamic system (4,5,8) which controls movement of the support, with an error detector (6) solidly attached to the aerial to determine a minimum signal condition. With the benefit of the dynamic support for the aerial, and the reference signal provided by the detector (71), the characteristics of an unknown external acoustic source may be determined.