| 摘要 |
<p>PURPOSE:To hold efficient relation between a position indicator and a tablet which are not connected physically by adding a signal for controlling the position indicator to a radio wave generated on the tablet side and providing a means which decodes the signal on the position indicator side. CONSTITUTION:The power supply grid plate 1 and radio wave detection plate 2 of the tablet are superposed on one over the other to form one coordinate input plate. The power supply grid plate l consists of two grid lines 11 and 12. The radio wave detection plate 2, on the other hand, has plural looped coils extended in an X and a Y direction respectively and they are connected to an X-axial scanner and a Y-axial scanner 36. A crystal oscillator 32 operates under the command of a processor 31 provided in an electric part and generates a clock of specific frequency. This clock is supplied to a frequency divider 37 to generate an operation clock for controlling the power supply grid plate 1 as the rear stage. A phase shifter 38 as a following stage applies a signal SIN and a signal COS to the grid according to the generated clock.</p> |
