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:
Nov. 06, 1990
Filed:
Jan. 04, 1990
Josef Beller, Reutlingen, DE;
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
In a method and a corresponding apparatus for performing optical time domain reflectometry predetermined time sequences of light signals (A', B') are injected into an optical fiber and the signals backscattered from the fiber are correlated with the injected sequences. The injected time sequences are selected according to a specific code such that after each element in the code represented by '1' or '-1', a predetermined number of elements represented by '0' is provided. Depending on the number of inserted '0's after each '1' or '-1', sidelobes in the correlation product appear at certain predictable positions. By choosing the numbers of inserted '0's differently for different injections, the resulting sidelobes appear at different positions in the corresponding correlation products. From the correlation products of such different injections, a composite fiber response can be derived wherein sidelobes are substantially eliminated. The codes used can be derived, for example, from Golay complementary codes.