Gas measurement apparatus and the setting method of width of wavelength modulation in gas measurement apparatus
US8896835B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2012 |
| Grant date | Nov 25, 2014 |
| Priority date | — |
| Expiry date | May 21, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/39
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A gas measurement apparatus measures a target gas. The gas measurement apparatus includes a light source, a first light receiving apparatus, a first phase-sensitive detection apparatus, an R calculation unit, and a setting unit. The light source oscillates a laser light that has a central wavelength determined by a main current and is modulated according to a modulation current, with the central wavelength being varied. The first light receiving apparatus outputs a detection signal according to an intensity of the laser light transmitted through a standard sample. The first phase-sensitive detection apparatus obtains a second harmonic component oscillated at a harmonic frequency ω2 twice as large as a modulation frequency ω1. The R calculation unit calculates a peak-bottom ratio R. The setting unit sets a width of wavelength modulation of the laser light so that the peak-bottom ratio R satisfies a predetermined condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.