| 摘要 |
<p>PURPOSE:To obtain a stable coordinate position with improved detecting accuracy by securing the coincidence between the center frequency of a band pass filter BPF and the main peak value of a vibration sensor and setting the band width at the value less than double sub-peak frequency. CONSTITUTION:A coordinate position is designated when the vibration transmitting plate 8 of an input tablet is depressed with an automatic pen 4. This pen 4 transmits an elastic wave and is constituted of a vibrator 5, a horn 6 and its supporter. A pen driving signal is produced by a driving signal generating circuit 2 with the instruction of a CPU 1 and applied to the vibrator 5. The elastic wave transmitted through the plate 8 is detected by a vibration sensor 7. The detected vibrating waveform is amplified by the amplifiers AMPa, AMPb and AMPc respectively and then inputted to the Tg and Tp detecting circuits via the BPFa, BPFb and BPFc. The CPU 1 acquires the coordinates of the designating point based on Tg and Tp.</p> |
