The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 16, 1989
Filed:
May. 20, 1987
Roland Heinze, Munich, DE;
Hakan Elmqvist, Baiersdorf, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
A measuring instrument for obtaining an intracardial signal indicative of blood oxygen saturation, which may be used to control the stimulation frequency of a heart pacemaker, has a measuring probe which contains a light transmitter and a light receiver. The light receiver receives light from the light transmitter reflected by the blood. The light transmitter and the light receiver are connected in parallel to an evaluation circuit via two leads. A constant current source is connected in series with the light transmitter. The current generated by the light receiver, indicative of blood oxygen saturation, can be identified by forming the difference between current flowing in the measuring probe and the constant current. A reference measurement to compensate for factors in the total current resulting from the lead resistances and the measuring probe temperature is not necessary.