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:
Jul. 25, 1989
Filed:
Feb. 27, 1987
Jurgen Kordts, Wedel, DE;
Gerhard Martens, Henstedt-Ulzburg, DE;
U.S. Philips Corporation, New York, NY (US);
Abstract
The invention relates to a method of taking measurements along an optical transmission path by means of an optical sensor. The optical sensor includes an optical converter whose optical attenuation properties can be influenced according to the value to be measured and through which a first beam portion of a high-frequency amplitude-modulated optical transmission beam is passed. A second beam portion of this transmission beam is conveyed via a delay element. The second beam portion is applied together with the first beam portion outputted by the optical converter, via the transmission path as a receive beam to the receiver arrangement. In this way the modulation change produced by the sensor is processed and evaluated as an information about the measure value. Measuring a value at the transmitter end is possible with any optical transmission path of an undefined length, without recalibration of the receiver arrangement, because the optical transmitter beam is additionally subjected to low-frequency modulation. An original modulation factor m.sub.o of the transmission beam is preset as the ratio of the high-frequency (I.sub.HF) to the low-frequency (I.sub.NF) modulation amplitude and is fed the receiver arrangement 3. The received sensor-influenced modulation factor of the receive beam is measured by the receive arrangement 3. The received-to-original modulation signal ratio is evaluated as information about the measuring value (M).