Measurement apparatus and measurement method
US11867809B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 2020 |
| Grant date | Jan 9, 2024 |
| Priority date | — |
| Expiry date | Apr 15, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A measurement apparatus includes a laser apparatus, a branching part that branches a frequency-modulated laser beam output by the laser apparatus into a reference light and a measurement light; a beat signal generation part that generates a beat signal by mixing a reflected light and the reference light, a conversion part that converts the beat signal into a digital signal at a first sampling rate and frequency-analyses it, an extraction part that extracts a signal component corresponding to a cavity frequency from the frequency-modulated laser beam, a digital filter that digitally filters the extracted signal component at a second sampling rate; and a calculation part that calculates a difference in a propagation distance between the reference light and the measurement light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.