| 摘要 |
<p>PURPOSE:To easily specify a three-dimensional coordinate by providing plural reference coils, and a movable coil which can move, so that exciting currents of each different frequency can be given to each reference coil. CONSTITUTION:Three pieces of reference coils 1-3 are contained in a tablet 4, to which a cursor 6 is connected through a lead wire 5. In this cursor 6, a movable coil 7 is contained, and it can move freely to the reference coils 1-3. Also, to the tablet 4, a CPU 8 is connected, and to the reference coils 1-3, exciting voltages of each different frequency are applied, and magnetic fields of each different frequency are generated. In this state, first of all. When the cursor 6 is moved against the tablet 4, a distance extending from the coils 1-3 to the cursor 6 is varied. A current induced in the coil by each reference coil has a frequency being equal to a frequency of the respective exciting currents. This induced current or voltage is digitized and inputted to the CPU 8. The CPU calculates a distance extending from each reference coil to the cursor, based on each frequency component.</p> |
