Coordinates reader

Abstract

Abstract PURPOSE: To simplify the circuit constitution as well as facilitate an easy control by applying the alternating field generated from the coordinates indicator to the lead wire on the tablet to detect the scale of the induced voltage and thus deciding the coordinates position. CONSTITUTION: When coordinates indicator 4 which generates the alternating field is put on tablet 1, the AC signal of frequency f 0 is induced to sense wires Xi and Yj each. This signal is piled on the scanning signal only when the scanning signals of scanner circuits 3X and 3Y are applied, and then led out to output line l through diode D. This signal is then amplifier 9 and then supplied to BPF10 which makes pass frequency f 0 to give discrimination, amplification 11 and smoothing 13 to the induced signal, and formed into the smooth waveform to then undergo amplification 14 and A/D conversion 15. Operation control part 16 gives the high-speed scanning to the sense wire and then leads in the induced voltage from converter 15 in sequence to obtain the coordinates value of the designated point from each voltage value. And the coordinates value, if obtained, is memorized temporarily; while in case the value cannot be obtained, the ineffective process is given. At the same time, the control is given to switch circuit 8, amplifier 9, external unit 22 and others in order to give compensation to the induction level difference of pens 4bW4c. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Yasuhiro Saito
• 👤 Takaomi Tatemichi

Bibliographic Details