Title:
【発明の名称】座標入力装置
Document Type and Number:
Japanese Patent JP2548746
Kind Code:
B2
Abstract:
PURPOSE:To accurately identify the use state of a position pointer by providing a transmission antenna coil and a reception antenna coil independently of each other. CONSTITUTION:A multiplexer 702g of a timing circuit 702 outputs a signal A where square waves having frequencies f1-f4 are repeated at intervals of a time 2T, and this signal is not only sent to a phase detector 710 but also converted to a sine wave signal by a reduction filter and is sent to the negative input terminal of an analog switch 704. The negative input terminal is selected while a switching signal B is in a high level, and the other input terminal is selected while it is in a low level; and therefore, a signal D which is outputted or not outputted in the time T appears in the output and is sent to a driving circuit 706 and is sent to a transmission coil 13, and the radio wave where frequencies f1-f4 are repeated at intervals of the time 2T is transmitted from the transmission coil 13 only for the time T. Consequently, a large AC signal is applied to the transmission coil 13.
Inventors:
TOMOFUJI YOSHIAKI
INESHIMA SATOSHI
INESHIMA SATOSHI
Application Number:
JP26102787A
Publication Date:
October 30, 1996
Filing Date:
October 16, 1987
Export Citation:
Assignee:
WAKOMU KK
International Classes:
G06F3/046; G06F3/03; G06F3/041; (IPC1-7): G06F3/033; G06F3/03
Attorney, Agent or Firm:
Yoshitaka Yoshitaka