| 摘要 |
<p>PURPOSE:To obtain an input position with high precision and to simplify the constitution of a detecting device, by producing the reference signal by mixing the signals which are applied from both ends of a plane resistor and have a prescribed phase difference and deciding the mixing ratio so as to obtain a coincidence of phase between the reference signal and the signal detected by an input pen. CONSTITUTION:The counter electrodes 121 and 122 are provided around a plane resistor 11, and the AC power supplies 14 and 15 having the same frequency omega and a phase difference phi are connected to the electrodes 121 and 122 via switches 131 and 132 respectively. An input pen 16 touches the resistor, and the position signal detected by the pen 16 is amplified by an amplifier 17 and then fed to one side of a phase comparator 18. At the same time, the power supplies 14 and 15 are connected to the reference input terminals of D/A converters 19 and 20 respectively, an the product of these power supplies and the output given from a digital control circuit 21 is applied to an adder 22. The output of the adder 22 is fed to the other side of the comparator 18, and the output of the comparator 18 is applied to the circuit 21. Then a coincidence is obtained for the phase difference between the reference signal and the signal detected by the pen 16. Thus the input coordinate value is obtained with high precision.</p> |
