ELECTROSTATIC-NOISE REMOVING CIRCUIT OF TABLET

PROBLEM TO BE SOLVED: To provide a noise removal circuit of a tablet for improving the performance of an electrostatic shield by removing noise from an output signal. SOLUTION: The electrostatic noise removal circuit is provided for the tablet provided with the shield 12 for supplying a signal adjusted to electrostatic noise and removing electrostatic noise from an information signal transmitted from a digital grid 10. Since the transparent conductive shield 12 is installed between the digital grid 10 and an image source 14, same electrostatic noise exists in both devices. The shield 12 is grounded at the shield end faces in zero to n-1 places. Here, (n) is the total number of the shield end faces. An electric signal is taken from a face which is not grounded, it is supplied to a differential amplifier 16 as an input signal and the information signal from the digital grid 10 is supplied as the other input signal from the differential amplifier 16. Thus, the signal outputted from the amplifier 16 becomes the information signal from which a noise signal component is removed.