| 摘要 |
<p>PURPOSE:To make it possible to perform high speed detection, by switching electrodes when the potential difference between switches is zero, so that the potential distribution on a flat resistor body is continued before and after the switching, and reducing the saturation of an input-pen detecting signal circuit. CONSTITUTION:A reference sine wave signal e1 and a sine wave signal e2 are compared in a voltage comparator 15. At an instance when the output of the comparator is changed from a ''0'' to a ''1'' (from a ''1'' to a ''0''), a switching signal is sent to switch driving circuit 5 from a T.FF circuit 16. At every time the output of the comparator 15 is changed, the output is reversed by the circuit 16. Electrodes are switched at every 1 period of the sine wave signal. When the switches are changed at the time the voltages of the signals e1 and e2 are the same, the potentials on the sides of the signal sources of the electrode switches at the instance of the switching are the same. The potentials on all the points on a flat resistor body become also the same. Therefore, currents do not flow through the switches. Generation of noise is few. Saturation of an input pen detecting signal circuit is reduced. A dynamic range is reduced. Thus a high speed detection can be performed.</p> |
