Blood constituent monitoring apparatus and methods with frequency division multiplexing
US4800885A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 2, 1987 |
| Grant date | Jan 31, 1989 |
| Priority date | — |
| Expiry date | Dec 2, 2007 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/14552
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus and method for measuring the level of a constituent such as oxygen in the blood of a living subject. Light at a plurality of wavelengths is emitted and directed through the patient's body to a photodetector. The amplitude of the emitted light at each wavelength is varied in accordance with a different carrier frequency, and the photodetector signal thus includes a component at each carrier frequency. Each such component represents transmissivity of the body structure at one wavelength of the emitted light. The photodetector signal is subdivided by frequency so as to separate the components at the different carrier frequencies. The constituent level is determined from these separated components.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.