DIGITIZER

PURPOSE:To attain an instructed coordinate arithmetic operation following the high speed movement of a position instructor by using an area where an induced voltage is the highest among surrounding 4 areas decided based on the moving direction of the position indicator and position information in a reference area, as the reference area, and measuring the induced voltage in 9 areas with the reference area as a center. CONSTITUTION:Four areas G, H, B, and C where a voltage value is measured are selected based on the position information of the last instructed coordinate and the moving direction of the position instructor. Then, the voltage value at those points is measured, and the center is moved to the area where the voltage is the highest, and used as the reference area. For example, when this area is defined as an area H, surrounding 8 areas L, M, N, G, I, B, C, and D with the reference area H as the center are decided, and the voltage of the points D, I, L, M, N whose voltage is not measured among those areas is measured. Then, a coordinate calculation is operated by a prescribed algorithm based on the voltage measured values of the 9 points including the point H. Thus, the instructed coordinate arithmetic operation can be attained following the high speed movement of the position instructor.