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. 21, 1992
Filed:
Jul. 23, 1991
Shigeki Kaneko, Kounosu, JP;
Takao Sakurai, Sano, JP;
Advantest Corporation, Tokyo, JP;
Abstract
An optical pulse of a fixed width is applied to an optical fiber, back scattering light from the optical fiber is converted to an electric signal, which is converted to a digital signal by sampling with a fixed period. In a difference calculating section an average of digital signals at a first sample point and at W sample points preceding the first sample point is used as data at the first sample point, and an average of digital signals at a second sample point and at W sample points following the second sample point, which is after the first sample point by a number of sample points corresponding to the width of the optical pulse, is used as data at the second sample point. The difference between the data at the first sample point and the data at the second sample point is calculated for each of a series of sample points to obtain difference waveform data. Changing points of the difference waveform data are detected and a spliced point of the optical fiber is decided, based on the detected changing points.