Method and apparatus for analog graphics sample clock frequency offset detection and verification
US8111330B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 2010 |
| Grant date | Feb 7, 2012 |
| Priority date | — |
| Expiry date | Nov 2, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0122
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for an analog-to-digital video signal converter. The converter is controlled by a clock with controllable frequency and phase for sampling an analog signal. A circuit corrects the clock frequency using a period of a columnar frame differences as a function of columnar location. The sampling clock frequency is changed by an amount dependent on the period of the columnar differences. A second measure of the difference between successive frames is computed for a sequence of clock phases. The frequency of the clock is verified using a characteristic of the second measure. The characteristic can be the ratio of the maximum to the minimum of the second measure over selected clock phases. Other characteristics can be used such as a difference of a maximum and a minimum measure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.