| 摘要 |
<p>PURPOSE:To obtain an accurate coordinate signal, by providing a circuit which detects the degree of getting out of shape in the symmetrical or asymmetrical property of signal waveforms indicating the position of a pen and corrects a coordinate detecting error caused by the inclination of the pen. CONSTITUTION:Signals (c) and (d) indicating the symmetrical property of a position signal are produced, by differentiating the position signal by means of a differentiation circuit 21 and taking the logic of a signal (a) obtained by binary-coding the output of the circuit 21 and another signal (b) obtained by binary-coding the position signal itself. Since the difference in the widths of the signals (c) and (d) represents the degree of inclination of a pen, clocks are respectively counted during the periods of both the widths by means of counters and access is made to a storage circuit 37 in accordance with both count amounts. Then a stored correcting quantity W is read out and coordinates are corrected. Various types of circuits other than the above-mentioned circuits can be used as an inclination detecting circuit 20 and correcting signal generating circuit 30.</p> |
