Digital compass and magnetometer having a sensor coil wound on a high permeability isotropic core

  • US 4,851,775 A
  • Filed: 07/02/1987
  • Issued: 07/25/1989
  • Est. Priority Date: 07/02/1987
  • Status: Expired due to Term
First Claim
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1. A magnetometer comprising:

  • an oscillator circuit comprising;

    oscillator driver means having first and second terminals for providing an oscillating current; and

    sensor means having a first coil wound on a first high permeability isotropic core for controlling the frequency of said oscillator circuit, said first coil coupled between said first and second terminals, said first coil having a magnetic axis;

    said oscillator driver means for providing a DC bias current through said first coil, such that when said sensor means experiences a change in an externally applied magnetic field, the frequency of the oscillating current changes monotonically with the change in magnitude of the applied external magnetic field in the direction of the magnetic axis of said first coil; and

    measurement means for measuring the frequency of the oscillating current and providing a measurement signal in response thereto.

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