Analogue-to-digital converter and analogue-to-digital conversion system embodying said converter
US5629699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1995 |
| Grant date | May 13, 1997 |
| Priority date | — |
| Expiry date | Jul 10, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F7/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An N-bit analogue-to-digital converter can increase the resolution by 3 bits, by very precise coding of the differential phase at the output of the electro-optic phase modulator controlled by the electric signal to be converted. The optical signals obtained are processed by an electro-optic device that outputs electric signals that are functions of the sine and cosine of the phase. A coding device uses the symmetry of the trigonometric circle partitioned into four consecutive sectors between 0 and 27.pi. in order to convert the absolute values of the electric signals obtained on (N-3) bits, independently of the home sector of the phase. A transcoding device uses the value of the sine and cosine coded on (N-3) bits, to output a value V of the electric signal, on N bits, as a function of the home sector. The conversion system according to the invention comprises a first N-bit analogue-to-digital converter doing a very precise but ambiguous conversion of the electric signal, and a second analogue-to-digital converter to eliminate the ambiguity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.