| 摘要 |
<p>PURPOSE:To overcome the instability of vibration detection due to that vibration is transmitted in two vibration modes and to enable stable coordinate input to be carried out. CONSTITUTION:The peak of signals obtained by detecting a first vibration pulse is held by a peak hold circuit 4b-1 and the value is voltage-divided by a fixed resistor 4b-4 and a variable resistor 4b-3 and inputted to a comparator 4b-2. The signal by a second pulse is inputted to the comparator 4b-2 and compared with the output of the peak hold circuit 4b-1. As a result, rectangular waves with a window are outputted only in a period when the second signal becomes equal to or more than a prescribed value. For the signals by the vibration pulses, a zero-cross point is detected within the period, the time from a vibration source to a detection point is measured with the time as the arrival time of vibration and coordinates are calculated based on it.</p> |
