| 摘要 |
<p>PURPOSE:To detect three-dimensionally the position of an oscillation source and then to detect a position indicated on a screen as well as this indicating direction, by receiving the ultrasonic waves oscillated from plural oscillation sources provided to an indicating means by plural receiving microphones provided on the indication screen. CONSTITUTION:The detection signal given from a central processing unit is sent to a one-shot pulse generating circuit for production of one-shot pulses. At the same time, the detection signal is also supplied to a counter as a start signal for start of the counting action. While the one-shot pulse is supplied to an oscillation source driver and the ultrasonic waves are delivered from the ultrasonic wave oscillation sources 6 and 7 provided to an indication pen 5. These ultrasonic waves are transmitted into the air and received by microphones 2-4 to undergo the amplification and waveform shaping. Then the amplified and shaped ultrasonic waves are supplied to the counter and stop the counting action. The count values of the counter showing the arrival times to the microphones 2-4 are sent to the central processing unit for calculation of the coordinate positions of both sources 6 and 7.</p> |
