Patent ID: 6474158
Filing Date: 2002-11-05
Classification: G01D,G01F

Abstract:
A sensor system for measuring displacement, the sensor system comprising:a primary coil wound around a longitudinal axis; at least one secondary coil wound around the longitudinal axis, each secondary coil having a winding density distribution that varies between the ends thereof, each secondary coil having a winding direction that varies between a clockwise winding direction and a counterclockwise winding direction between opposite ends thereof; a coupler positioned adjacent the primary coil between the ends thereof, the coupler including a resonating circuit configured to resonate at a resonating frequency; and a control system which excites the primary coil with a first step of a signal and which receives from each secondary coil in response thereto a time varying signal, wherein: at least one of (i) the coupler and (ii) the primary and secondary coils are configured to move relative to the other of the coupler and the primary and secondary coils; each time varying signal includes a ringing component superimposed on a time varying component temporally adjacent the first step of the signal; and the control system acquires one or more values of each time varying signal after the ringing component thereof dissipates and determines therefrom a position of the coupler along the longitudinal axis.