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. 27, 2025
Filed:
Oct. 17, 2019
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo, JP;
Abstract
An object of the present invention is to propose a design method of a minimum value N of the number of multiplexed frequencies that is necessary for measuring an object vibrational frequency according to DAS-P while taking into consideration a trade-off between a measurement distance and an upper limit of a measurable vibrational frequency. When a phase change of an arbitrary section of a measured optical fiber is represented by A×sin(2πfvt), N=4Zfv/ν is satisfied when A is smaller than π/2 but N=2Zfv/(ν·Arcsin (π/2A)) is satisfied when A is equal to or larger than π/2, where fv represents vibrational frequency, t represents time, Z represents a length of the measured optical fiber (a measurement distance), and ν represents the speed of light inside the measured optical fiber.