Electrical circuit, apparatus and method for the demodulation of an intensity-modulated signal
US7595476B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 2004 |
| Grant date | Sep 29, 2009 |
| Priority date | — |
| Expiry date | Sep 13, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D7/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A modulated optical radiation field (I) whose modulation amplitude and temporal phase depend on the local position can be detected with a plurality of pixels 1. Each pixel 1 consists of a transducing stage (T) that converts incoming light (I) into a proportional electric signal, a sampling stage (S), two subtraction/summation stages (SUB1, SUM1; SUB2, SUM2), and an output stage. Each pixel can be addressed individually. The optical radiation field (I) is locally sensed and sampled at a frequency that is four times the wavefield's modulation frequency. The subtraction/summation stages (SUB1, SUM1; SUB2, SUM2) accumulate differences of two samples per modulation period, separated by half the period, during several averaging periods; the two stages are time shifted with respect to each other by a quarter period. The resulting two output signals are employed for the determination of the local envelope amplitude and the temporal phase. These pixels 1 can be realized with circuits that consume very little electric power require small areas, enabling the realization of large numbers of pixels in linear or two-dimensional array sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.