摘要 |
A tablet input device includes a manipulation pad with a group of parallel drive lines and a group of sense lines which are interlaced in parallel with the drive lines. A drive circuit is provided which sequentially scans the drive lines with a variable drive current. When an input pen indicates a point on the face of the manipulation pad and when one of the drive lines adjacent to this point is excited, a voltage is induced across one or more sense lines adjacent the excited drive line. A sense circuit is provided which detects the magnitude or the polarity of the induced voltage, thereby detecting the address of the point indicated by the input pen.
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