| 摘要 |
<p>PURPOSE:To correct the phase characteristic of a circuit and to correct phase fluctuation on account of a temperature change in a wireless coordinate reader which detects the switch of a coordinate indicator from the phase change of a guide signal. CONSTITUTION:The signal change-over switch 16 selecting an exciting signal and the guide signal and inputting them to an amplifier circuit and a filter, a correction value storage circuit 17 storing the phase difference amount of the exciting signal which is selected by the signal change-over switch 16 and which passes through the amplifier circuit 8 and a band pass filter 9 in a phase detection circuit 14 as a correction value, and a correction circuit 18 correcting the phase difference amount of the guide signal which is selected by the signal change-over switch 16 and which passes through the amplifier circuit 8 and the band pass filter 9 in the phase detection circuit 14 as the correction value stored in the correction value storage circuit 17 are provided.</p> |
