Upward-folding successive-approximation optical analog-to-digital converter and method for performing conversion
US6121907A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1998 |
| Grant date | Sep 19, 2000 |
| Priority date | — |
| Expiry date | Aug 11, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F7/00
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical analog-to-digital converter (10) which fully operates in the optical domain and utilizes an upward-folding successive approximation approach for conversion. The converter (10) includes a plurality of optical stages (14, 16, 18) where each stage (14, 16, 18) generates a digital bit. Each stage (14, 16, 18) includes an optical threshold switch (30, 56, 78) that sets the bit high when the switch (30, 56, 78) is closed. When a sample amplitude of the analog signal is compared to a threshold value and found to exceed the threshold value, the bit is set to "high" and the sample is passed directly onto the next stage (14, 16, 18). If the sample amplitude is found to be less than the threshold value, the bit is set to "low" and an intensity equal to the maximum signal intensity minus the threshold intensity is added to the sample amplitude. Each successive stage (14, 16, 18) compares the normalized signal sample to thresholds growing closer and closer to the maximum signal intensity. Multiple bits can be obtained by cascading stages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.