04800885 is referenced by 230 patents and cites 2 patents.

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.

Title
Blood constituent monitoring apparatus and methods with frequency division multiplexing
Application Number
7/127835
Publication Number
4800885
Application Date
December 2, 1987
Publication Date
January 31, 1989
Inventor
Eric N Johnson
Boulder
CO, US
Agent
Larry R Cassett
Roger M Rathbun
Assignee
The BOC Group
NJ, US
IPC
A61B 5/00
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