| 摘要 |
<p>PURPOSE:To realize a coordinate inputting device with a small-scale circuit, by determining coordinates positions by performing envelope detection and detecting the peak position. CONSTITUTION:A signal (a) induced by a coil in a pen 7 is sent to a filter amplifier 31 after the voltage of a carrier for burst modulation is added to the voltage of the signal (a) at a combining circuit 70 and a signal (f) which is amplified while a side band component corresponding to a burst frequency component is suppressed is obtained by means of the amplifier 31. The signal (f) is subjected to envelope detection by means of a detector 61 and a signal (g) is obtained and a signal (h) indicating a speak position is produce by means of a clipping circuit 62 and peak detecting circuit 33. A coordinate generating circuit 8 outputs a coordinate signal from the time difference between a signal (i) indicating a reference position and the above-mentioned signal (h).</p> |
