04781195 is referenced by 185 patents and cites 3 patents.

In photoelectric apparatus such as a pulse oximeter for monitoring a parameter of the blood in a living organism, a dark current correction signal is applied to the input at the preamplifier. The correction signal is substantially equal in magnitude but opposite in sense to the photodetector output during dark intervals when the illumination means of the apparatus is disabled. Because dark current correction is accomplished at the input of the preamplifier, the preamplifier has substantially increased resistance to overloading caused by ambient light and hence may have higher gain.

Title
Blood monitoring apparatus and methods with amplifier input dark current correction
Application Number
7/127742
Publication Number
4781195
Application Date
December 2, 1987
Publication Date
November 1, 1988
Inventor
Alan D Martin
Boulder
CO, US
Agent
Roger M Rathbun
Larry R Cassett
Assignee
The BOC Group
NJ, US
IPC
G01N 33/49
A61B 5/00
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