| 摘要 |
<p>PURPOSE:To precisely and stably detect coordinates basically without any influence upon a human body and other disturbance by using a parallel signal transmitting means without utilizing a signal return path formed by dummy grounding wherein there are many unstable requests. CONSTITUTION:The sine wave generator 1 of an active circuit is arranged in a detection pen 5 and generates a continuous sine wave voltage. The balanced output of this sine wave generator 1 is applied to the stylus conductor 3 and ring-shaped conductor 4 at the tip part of the detection pen. The stylus conductor 3 and ring-shaped conductor 4, when present nearby the board surface of a tablet 6, are connected to respective electrode lines 7 of the tablet 6 with small electrostatic capacity. Then X-directional and Y-directional analog multiplexers 8 and 9 while switching two adjacent electrode lines among electrode lines 7 in pairs, apply balanced voltage signals to a balanced-to-unbalanced converter 10. The output of the converter 10 is converted into an unbalanced signal of pair ground level, which is applied to a band-pass filter 11.</p> |
