Abstract: An electrographic system utilizing a transparent resistive layer which operates in conjunction with a stylus or cross hair cursor excited from an a.c. source to develop coordinate defining electrical signals. Through the utilization of a sequence of border switching arrays, the signals may be collected from the resistive surface in a predetermined sequence and submitted in serial fashion to the input of a signal treatment network. As a consequence, only one such network is required to effect operation of the system. The hand-held cursor is formed including a transparent disk carrying cross hairs which is excited from an a.c. source to very accurately locate coordinate positions upon the resistive surface.

Abstract: An electrographic system utilizing a singular resistive layer which may be transparent in conjunction with a supportive substrate. Through the use of an electromagnetic field generating sytlus in conjunction with coordinate alternating border switching, linear output performance is achieved. With the utilization of sum, difference and divider circuitry in conjuction with received output signals, the system remains immune from voltage variations occasioned in conjunction with the stylus and, thus, the stylus may be operated in varying spaced-relationship from the resistive surface.