| 摘要 |
PURPOSE:To eliminate electrostatically induced malfunction in coordinate reading due to a stray capacity generated by the hand, by performing comparative subtraction at an arithmetic control section. CONSTITUTION:Scanning circuits 3X and 3Y scan each sense line Xn and Ym. A coordinate indicator 4 has a coil 5 while generates induction signals to the sense lines Xn and Ym. An amplifying filter circuit 7 applies waveform processing to an induction signal (l) from the sense lines Xn and Ym. An AD converter 8 performs AD conversion on a signal from the amplifying filter circuit 7. In short, the scanning circuits 3X and 3Y, amplifying filter circuit 7, and AD converter 8 constitute a scanning and detecting circuit. An arithmetic control section 9 operates the position of the coordinate indicator 4 by using a signal from the AD converter and, at the same time, controls the other external inputs and outputs. |
