| 摘要 |
<p>PURPOSE:To always accurately identify the state of a position indicator even when a phase deviation is generated in a receiving system of a device by detecting a phase obtained when an AC signal is directly sent to the receiving system of the device, and detecting a phase difference between a voltage and a current in a tuning circuit from the detected phase. CONSTITUTION:When the oscillation of radio waves from an antenna coil 13 is stopped an induction voltage is gradually attenuated, but a current having a phase difference corresponding to the state of the position indicator at this time, flows into the tuning circuit 22 and reflected radio waves are radiated a coil in the tuning circuit 13. The reflected radio waves are received by the antenna coil 13 being stopped the transmission of radio waves, and the phase of the received signal is obtained by adding the deviation of the phase in the receiving system of the device to the phase based upon the phase difference between the voltage and current of the tuning circuit 13. When an AC signal is directly sent to the receiving system of the device, the deviation of the phase is detected and the deviation of the phase is subtracted. Consequently, the phase of the receiving signal, i.e. the phase difference between the voltage and current of the tuning circuit 13, is detected and the state of the position indicator 2 is identified.</p> |
