Patent ID: 7821256

Claim:
An apparatus for providing a signal related to a position of a part, the apparatus including: an exciter coil, the exciter coil generating magnetic flux when the exciter coil is energized by a source of electrical energy; a receiver coil, disposed proximate to the exciter coil, the receiver coil generating a receiver signal when the exciter coil is energized due to an inductive coupling between the receiver coil and the exciter coil, the receiver coil having a plurality of sections, the inductive coupling tending to induce opposed voltages in at least two of the sections, the inductive coupling being modified by movement of the part so that the receiver signal is related to the position of the part; and a reference coil, the reference coil providing a reference signal when the exciter coil is energized due to inductive coupling between the reference coil and the exciter coil, the reference signal being substantially independent of the position of the part.