| 摘要 |
A cursor for taking position signals from a grid is includes a coil through which inductive coupling with the grid is established. Because inductive coupling is employed, there need be no physical contact between the cursor and the grid. The cursor is configured so that the effects of orientation changes of the sensor parallel to the plane of the grid are eliminated and the effects of orientation changes normal to the plane of the grid are minimized. Furthermore, the cursor includes a low reluctance magnetic element which provides a low impedance path for the magnetic flux within the cursor. An air gap is provided in the low reluctance element in the vicinity of the cursor which is in the closest proximity to the grid so that the magnetic field is concentrated at the grid, thereby permitting inductive coupling without the cursor physically contacting the grid.
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