Patent ID: 8686715
Filing Date: 2014-04-01
Classification: G01R

Abstract:
1. An impedance tuning method to null the effect of the terrestrial residual magnetic field on a Giant Magneto-Impedance magnetic sensor having a Giant Magneto-Impedance fiber, comprising: installing a Giant Magneto-Impedance magnetic sensor in a zero geo-field environment, wherein one or more electronic connections connected to the Giant Magneto-Impedance magnetic sensor are accessible to obtain a sensor output; recording a first sensor output from the Giant Magneto-Impedance magnetic sensor in the zero geo-field environment; installing the Giant Magneto-Impedance magnetic sensor in an intended operating environment subject to a geo-field; recording a second sensor output from the Giant Magneto-Impedance magnetic sensor in the intended operating environment; making a determination of the nature of the Giant Magneto-Impedance fiber impedance in the Giant Magneto-Impedance magnetic sensor based on at least the first and second sensor outputs, wherein the nature of the reactance is categorized from three categories: resistive, capacitive, and inductive; and activating, based on the nature of the Giant Magneto-Impedance fiber impedance, a series and parallel combination of a plurality of resistors, inductors and capacitors in an impedance tuning circuit that is part of an impedance matching network comprised of integrated circuit components and electrically connected to said Giant Magneto-Impedance magnetic sensor, in order to affect a compensating impedance that is equal but opposite to an impedance represented by the difference between the first and second sensor outputs.