| 摘要 |
<p>PURPOSE:To sharply shorten the detection time of a coordinate indicator by respectively dividing sense line groups laid along XY coordinate axes into plural blocks and simultaneously exciting sense lines in each block. CONSTITUTION:Blocks y1, y2 in the 1st sense line group S1 are simultaneously started to be scanned and an alternative magnetic field is generated. In the 2nd sense line group S2 also, blocks x1, x2 are simultaneously started to be scanned. A resonance circuit in the coordinate indicator 20 resonates by the alternative magnetic field applied from the group S1 and an induction signal is induced in the group S2. The induction signal is amplified, shaped at its waveform and compared with a proper threshold by a control circuit 14 to recognize the existence of the indiator 20 and store a current address. Then the circuit 14 starts scanning in each block of the groups S1, S2. Since an induction signal is generated only in the block including the indicator 20, the position of the indicator 20 can be detected.</p> |
