Optical spatial frequency measurement
US6501258B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 2001 |
| Grant date | Dec 31, 2002 |
| Priority date | — |
| Expiry date | Sep 28, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R23/17
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A signal processing apparatus for providing electrical frequency measurements of input signals. In one embodiment, a power splitter divides an RF input signal into first and second input signals. An RF channelizer having a filter bank receives the first input signal and determines a coarse frequency measurement. An optical modulator modulates an optical carrier signal with the second input signal, and a beam splitter divides the modulated carrier signal into a plurality of optical signals that each feed into one of a plurality of optical frequency discriminators (“OFD”). Each OFD uses a fiber optic delay line and spatial domain sampling techniques to extract a phase measurement. An ambiguity resolver receives the phase measurement from each OFD and determines a single, absolute phase measurement, which is translated to a fine frequency measurement. A frequency encoder combines the coarse and fine frequency measurements to produce a final frequency measurement having increased resolution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.