Analog sampling system and method for noise supression
US9600707B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 2016 |
| Grant date | Mar 21, 2017 |
| Priority date | — |
| Expiry date | Jun 29, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1329
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
There is provided a capacitive fingerprint sensing device comprising a plurality of sensing elements, sensing circuitry for providing an analog sensing signal, drive signal circuitry providing a drive signal comprising a drive pulse having a maximum level and a minimum level, providing a change in potential difference between the finger and the sensing structure, analog sampling circuitry comprising at least three analog sample and hold circuits arranged to sample the sensing signal, and a sampling control unit for individually controlling the sample and hold circuits to capture a sample at a specified time, wherein the samples comprises one sample captured when the drive signal is at a first voltage level V1 and one sample captured when the drive signal is at a second voltage level V2, different from V1; and an analog-to-digital converter, ADC, configured to convert a combination of the samples into a digital signal, wherein the three samples are captured times such that a noise component is suppressed from the sensing signal when the combination is formed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.