发明名称 Method and apparatus for eliminating an offset signal in an electrostatic digitizing tablet
摘要 <p>The present invention provides for a method and apparatus for detecting when a second object touches a digitizing panel (14) while a first object is already touching the digitizing panel (14). The method includes the steps of generating a first composite signal including a first touch-down signal component and an offset signal component when the first object touches the digitizing panel (14) converting the first composite signal to a first digital value indicative of an amplitude of the first composite signal, filtering the first digital value to filter out the offset signal component and to output the first touch-down signal component, generating a second composite signal including a second touch-down signal component and a first composite signal component when the second object touches the digitizing panel (14), converting the second composite signal to a second digital value indicative of an amplitude of the second composite signal, and filtering the second digital value to filter out the first composite signal and to output the second touch-down signal component. &lt;IMAGE&gt;</p>
申请公布号 EP0789318(A1) 申请公布日期 1997.08.13
申请号 EP19970300851 申请日期 1997.02.10
申请人 SYMBIOS, INC. 发明人 TETERWAK, JERZY A.
分类号 G06F3/044;G06F3/033;G06F3/041;G06F3/045;(IPC1-7):G06K11/16 主分类号 G06F3/044
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