The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 1991
Filed:
May. 22, 1990
Jason Hoendervoogt, Phoenix, AZ (US);
Brian Abernethy, Phoenix, AZ (US);
CalComp Inc., Anaheim, CA (US);
Abstract
A driving grid is driven by an ac signal comprising a carrier frequency modulated by a lower frequency. An untethered, batteryless pointer includes a pick-up coil in a first tuned circuit tuned to the carrier frequency, connected by diodes to a driving coil in a second tuned circuit tuned to the lower modulating frequency. Energy picked up by the first tuned circuit from the driving grid at the carrier frequency drives the second tuned circuit at the modulating frequency. Modulating frequency signals induced in the receiving grid conductors are used to locate the pointer in the usual manner. Because the carrier signal contains no frequency component of the modulating signal, the driving grid and receiving grid are sufficiently decoupled.