Noise cancellation for non-ideal electrostatic shielding
US5574262A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Oct 4, 1994 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Oct 4, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2203/04107
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Cancellation of electrostatic noise in digitizing tablet having a shield supplying a signal proportional to the electrostatic noise which is subtracted from the information signal derived from a digitizing grid. A conductive transparent shield is interposed between a digitizing grid and image source so that the same electro-static noise on both. The shield may be grounded on zero to n-1 edges, n being the number of edges of the shield. An electrical signal is taken from an ungrounded side and supplied as an input signal to a difference amplifier, the other input signal being the information signal from the digitizing grid. The output signal from the amplifier is the information signal with the noise signal component cancelled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.