| 摘要 |
<p>PURPOSE:To reduce the cost and to improve the operability by outputting a switch signal, when a phase to be detected is varied by a prescribed quantity. CONSTITUTION:A phase of a voltage of a detection resistance 2d and a phase of a drive signal 2a are compared by a phase comparator 2f, and stored as phase data in a microcomputer 2h. Subsequently, the phase detection is continued, and phase data which is detected is compared with the phase data which is stored earlier in the microcomputer 2h. When a prescribed phase shift has existed in a result of its comparison, the microcomputer 2h decides that a pen point is pressed and outputs a switch signal 2g.</p> |
