Abstract: A device for determining position coordinates of points on a surface, has a tablet containing plural number of equally spaced driver windings and plural number of equally spaced sense windings. Each driver winding has a pair of parallel conductors laid in X-direction, and each sense winding has a pair of parallel conductors laid in Y-direction. A current is generated in a cursor coil by the voltage induced from the current in a nearby situated driver winding. This current in the cursor coil induces a voltage in a nearby situated sense winding. The X-position of a sense winding in which a maximum voltage is induced, and the Y-position of a driver winding which induces a maximum voltage in the cursor coil, determine the position coordinates of the cursor on the tablet. Auxiliary sense windings are supplemented to the tablet. Induced voltages on these auxiliary sense windings determine the Y-position of the cursor regardless of its X-position, and reduce the overall time required for position determination.

Abstract: A device for determining position coordinates of points on a surface, have a cursor structure, a grid structure, and a signal processor. The cursor structure has a cursor coil and a signal generator to impress a reference phase voltage to the coil. Voltages induced from the cursor coil in conductors of the grid structure are processed in the signal processor to produce a position dependent phase voltage. For the signal processor, reference phase pulses are obtained from a voltage induced in an auxiliary grid conductor provided in the grid structure.