| 摘要 |
<p>PURPOSE:To obtain a small-sized coordinate input device by scanning alternately two electric conductor loop groups, and sending out a coordinate signal of an input part in accordance with a time difference of a pulse signal corresponding to the original point, and a signal for showing a peak time. CONSTITUTION:On the input surface of a tablet 1, a proceeding magnetic field in X and Y coordinate axis directions is generated alternately in accordance with a switching signal sent from a controlling circuit 6. A signal induced in a coil in a pen at the time of an input is sent to a detecting circuit 30, and a filter amplifier 31 eliminates a high frequency component and sends a signal (f) having a smooth envelope to a detector 32. The detector 32 detects the signal (f) and sends a signal (g) to a peak detecting circuit 33, generates a signal (h) whose pulse signal rises at the time of a peak of a waveform of the signal (g), and sends it to a coordinate generating circuit 8. The coordinate generating circuit 8 generates a digital signal of a value proportional to a pulse interval time (t) of a signal (i) whose pulse rises by timing corresponding to the original point of each coordinate sent from the controlling circuit 6, and the signal (h), and sends it out as a coordinate signal.</p> |
