| 摘要 |
<p>PURPOSE:To increase the position detection speed by using a reception circuit holding the value of the induced voltage when the prescribed time shorter than the signal delay time caused by a BPF lapsed after a loop coil is switched. CONSTITUTION:The signal produced by the voltage induced at a tuning circuit 41 of a position pointing device 4 is delayed by a reception circuit 6 by a signal delay time set by a BPF. Then the circuit 6 holds the value of the induced voltage when the prescribed time shorter than the delay time lapsed after the loop coils (11-1)-(11-48) are switched. Thus each loop coil can obtain the induced voltage which is gradually reduced as the distance increases from the position designated by the device 4 with the induced voltage of the loop coil set nearest the designated position. The value of each induced voltage is computed by a processor 7 and the coordinate value is obtained for the position designated by the device 4. Consequently, the position detecting speed is increased even with the use of a BPF having the small width of its frequency band.</p> |
