Self calibrating dual range A/D converter
US5164726A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 12, 1991 |
| Grant date | Nov 17, 1992 |
| Priority date | — |
| Expiry date | Jun 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/188
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A dual range A/D converter includes a gain matching circuit for balancing the upper end of the transfer curves of the level-dependent dual A/D signal paths of the converter so as to control crossover between the paths. One path (high gain path) is provided with signal gain that is a nominal multiple of gain applied to the other path (low gain path). A digital comparator compares the digital code word output of flash A/D converters included in the respective paths, with the output from the high gain path being scaled down to correspond to the output from the low gain path. If a difference is detected, the upper ladder reference of the flash converter in the low gain path is adjusted until the respective gain difference becomes substantially an exact multiple. When this matching is combined with black level correction, which equalizes the lower end of the transfer curves, a fully self-calibrating dual range A/D converter is obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.