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:
Jan. 22, 1980
Filed:
Jul. 03, 1978
George A Fencl, Phoenix, AZ (US);
Talos Systems, Inc., Scottsdale, AZ (US);
Abstract
A low noise system and method are provided for sequentially sensing induced signals in a plurality of digitizer grid conductors. The digitizer includes a coil disposed above the tip of a pen. The coil induces the signals in the grid conductors. The system includes scanning circuitry which sequentially scans the grid conductors, which are oriented in an X direction and a Y direction, causing the induced signal to be sequentially coupled to the input of a differential amplifier. The X and Y grid conductors each have first ends connected to corresponding inputs of first and second multiplexers. The X and Y grid conductors each also have corresponding second ends connected to first and second corresponding common conductors. The outputs of the first and second multiplexers are coupled, respectively, to first and second inputs of the differential amplifier. The first and second common conductors are coupled, respectively, to the outputs of the second and first multiplexers. In one embodiment of the invention, each group of grid conductors is divided into subgroups of conductors each having their first ends respectively connected to corresponding inputs of a first multiplexer. The second ends of the conductors of each subgroup are coupled to a common conductor by isolation diodes having their anodes connected to that corresponding common conductor. The respective common conductors are connected to corresponding inputs of a second multiplexer having its output connected to the second input of the differential amplifier.