Method and apparatus for determining the absorption of electromagnetic radiation by a gas
US5506685A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 1, 1996 |
| Grant date | Apr 9, 1996 |
| Priority date | — |
| Expiry date | Mar 1, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/39
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention provides a method consisting successively in producing two electromagnetic radiations of the same wavelength that is modulated as a function of time over a range of wavelengths, a "measurement" one of said radiations passing through a gas that presents selective absorption for said radiation in the range, while the other radiation constitutes a "reference" radiation. Each of said radiations is transformed into a respective "measurement" or "reference" electrical signal. The measurement signal is divided by the reference signal to obtain a first quotient electrical signal which is in turn split into two portions: a time-varying AC portion and a DC portion that does not vary with time. The AC portion is divided by said DC portion in order to obtain a second quotient electrical signal representative solely of the electromagnetic radiation absorbed by the gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.