JPS6459420A - Coordinate input device - Google Patents

Abstract

PURPOSE:To prevent an erroneous input by making a peak detecting operation inactive for a prescribed time after having detected a peak of a detecting signal waveform of a vibration sensor, when it is confirmed that a detecting signal of the vibration sensor is a detecting signal of a vibration which is inputted from a vibration pen. CONSTITUTION:By detecting the zero crossing of a peak of a vibration detecting waveform, the waveform detection timing can be determined, irrespective of whether the amplitude of a wave of a peak is large or small, therefore, irrespective of writing pressure of a vibration pen 3, and a vibration transfer distance namely, an input position on a vibration transfer plate 8, the vibration transfer time can be measured exactly. Also, an arithmetic control part 1 counts an output of level comparators 60, 60' by using counters 21, 21'. In such a way, the control can be executed so that an erroneous detection is not executed due to a reflected wave, and disturbance noise.