| 摘要 |
<p>PURPOSE:To exactly detect the coordinate of a pen point even when a input pen is inclined by performing a correcting operation for the detected coordinate, including an error, based on a peak point and a peak level value. CONSTITUTION:A scanning is carried forward successively from 0-th electrode by making a sinusoidal current flow, and at the pk1-st electrode, a peak detector 101 detects a peak from the output signal b1 of a BPF 70, and a peak holding circuit 103 holds its level. Successively, at the L-th electrode, the phase of the signal b1 is inverted, and a comparator 73 outputs a phase inversion signal, and the value L of a counter 82 is latched to a latch 83. Successively, at the pk2-nd electrode, the peak detector 102 detects the peak, and the peak holding circuit 104 holds the said level e2, and the latch 114 latches the pk2. The levels e1, e2 are A/D-converted, and go to ed1, ed2. Then, a distance between a point K, just below the input pen 4, and a phase changing point L, i.e., (pk2-L)X(ed1-ed2)/(ed1+ed2) is calculated by operating elements 107-112, and the point K is obtained by subtracting the L from this value. This processings are executed in both X, Y directions, and the correct coordinate is obtained.</p> |
