Patent ReferencesMagnetic compass compensation system Single frequency noise reduction circuit for squids Superconducting magnetic field sensing apparatus having digital output, on-chip quantum flux packet feedback and high bias margins Patent #: 5248941 InventorsAssigneeApplicationNo. 881795 filed on 05/12/1992US Classes:324/248, Superconductive magnetometers505/846Using superconductive quantum interference device (i.e., SQUID): (Class 324/248)ExaminersPrimary: Snow, Walter E.Attorney, Agent or FirmInternational ClassG01R 033/035Foreign Application Priority Data1991-05-13 JPAbstractA magnetic noise reducing device can effectively produce a practically noiseless space that can reduce environmental magnetic noise harmful for measuring biomagnetism with a high magnetism damping factor in low frequency range. The magnetic noise reducing device comprises a SQUID flux meter 1 and a pair of noise canceling coils 2 as minimum components, the feedback current I produced by the SQUID flux meter 1 being supplied to the noise canceling coils 2, the magnetic flux detecting coil of the SQUID flux meter being arranged within a specific central space 4 defined by the noise canceling coils 2 for effective reduction of magnetic noise within that space. | |