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1. 发明公开

EP3951334A1 PHASE MEASUREMENT METHOD AND SIGNAL PROCESSING DEVICE 有权
公开(公告)号：EP3951334A1
公开(公告)日：2022-02-09
申请号：EP20783029.0
申请日：2020-03-19
申请人： NIPPON TELEGRAPH AND TELEPHONE CORPORATION
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , TOGE, Kunihiro , OSHIDA, Hiroyuki
IPC分类号： G01H9/00 , G01D5/353
摘要： It is intended to provide a phase measurement method and a signal processing device that are capable of reducing influence of noise of a measuring device without increasing the peak intensity of an incident light pulse when measuring the phase of scattered light in DAS-P.
A phase measurement method according to the present invention causes wavelength-multiplexed pulse light to be incident on a measurement target optical fiber, produces a scattered light vector obtained by plotting scattered light from the measurement target optical fiber for each wavelength onto a two-dimensional plane having the in-phase component thereof on the horizontal axis and the orthogonal component thereof on the vertical axis, rotates the produced scattered light vector for each wavelength at each place in the measurement target optical fiber to align the directions of the vectors, generates a new vector by calculating the arithmetic average of the vectors having the aligned directions, and calculates the phase by using the values of the in-phase and orthogonal components of the generated new vector.

2. 发明公开

EP4354099A1 SIGNAL PROCESSING DEVICE, VIBRATION DETECTION SYSTEM, AND SIGNAL PROCESSING METHOD 审中-实审
公开(公告)号：EP4354099A1
公开(公告)日：2024-04-17
申请号：EP21945112.7
申请日：2021-06-09
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , KOSHIKIYA, Yusuke , HONDA, Nazuki
IPC分类号： G01H9/00
CPC分类号： G01H9/00
摘要： The present disclosure aims to remove the influence of an uncorrected angular difference, even in a state where the multiplexing number allocated to reduction of fading noise is small and the angular difference between the respective main optical frequencies is completely uncorrectable.
The present disclosure relates to a signal processing device that: acquires a signal obtained by repeatedly injecting a plurality of light pulses with different optical frequencies into an optical fiber, and by performing distributed acoustic sensing-phase (DAS-P); calculates a phase change, caused by vibration applied to a section of the optical fiber, using the acquired signal; removes, from the calculated phase change, a component regarding a repetition period of the same optical frequency of the plurality of light pulses; and calculates the vibration applied to the section of the optical fiber, using a phase change obtained by removing the component regarding the period.

3. 发明公开

EP4212834A1 VIBRATION DETECTION APPARATUS AND VIBRATION DETECTION METHOD 审中-实审
公开(公告)号：EP4212834A1
公开(公告)日：2023-07-19
申请号：EP20953319.9
申请日：2020-09-11
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , OKAMOTO, Tatsuya , HONDA, Nazuki , OSHIDA, Hiroyuki
IPC分类号： G01H9/00
摘要： An object is to provide a vibration detection apparatus and a vibration detection method which can avoid occurrence of a point where detection sensitivity deteriorates in vibration detection of a scattered light intensity monitor according to optical frequency multiplexing.
The present invention conceives a multi-dimensional space having as many dimensions as the number of frequencies to be used, causes scattered light intensity change at each optical frequency to correspond to each axis, plots a scattered light signal as a vector on the space, performs linear approximation passing through an origin on the space having a plurality of plotted vector points as original data, and performs vibration detection using a direction vector of an approximate straight line obtained as a result of the approximation.

4. 发明公开

EP4296624A1 SIGNAL PROCESSING METHOD AND SIGNAL PROCESSING DEVICE 审中-实审
公开(公告)号：EP4296624A1
公开(公告)日：2023-12-27
申请号：EP21932940.6
申请日：2021-03-23
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , OKAMOTO, Tatsuya , IIDA, Daisuke , KOSHIKIYA, Yusuke , KIKUCHI, Masashi , HONDA, Nazuki
IPC分类号： G01D5/353
摘要： A signal processing device (19) executes a phase connection process step of performing a phase connection process on a position in a space and a phase value at each of a plurality of times, a first correction step of performing outlier correction of a phase value for each position in the space in a predetermined direction of the space at a predetermined time among the plurality of times based on a result of the phase connection process, and a second correction step of correcting a phase value at a time other than the predetermined time for each of correction target positions in the first correction step among positions in the space.

5. 发明公开

EP3889560A1 PHASE MEASUREMENT METHOD, SIGNAL PROCESSING DEVICE, AND PROGRAM 有权转让
公开(公告)号：EP3889560A1
公开(公告)日：2021-10-06
申请号：EP19890160.5
申请日：2019-11-14
申请人： NIPPON TELEGRAPH AND TELEPHONE CORPORATION
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , OKAMOTO, Keiji , OSHIDA, Hiroyuki
IPC分类号： G01H9/00 , G01J9/00 , G01M11/02
摘要： It is an object to enable offline measurement with a high SN ratio of the phase of scattered light of an optical fiber to be measured in an optical receiving system for real-time measurement (direct measurement). The phase measurement method according to the present invention performs coherent detection of scattered light using a 90-degree optical hybrid, obtains an estimated quadrature component value by averaging a measured quadrature component value that is directly measured and a calculated quadrature component value obtained by Hilbert transforming a measured in-phase component value that is directly measured, obtains an estimated in-phase component value by averaging the measured in-phase component value and a calculated in-phase component value obtained by inverse Hilbert transforming the measured quadrature component value, and calculates the phase of scattered light based on the estimated quadrature component value and the estimated in-phase component value.

6. 发明公开

EP4412108A1 OPTICAL PULSE TESTING METHOD AND OPTICAL PULSE TESTING DEVICE 审中-实审
公开(公告)号：EP4412108A1
公开(公告)日：2024-08-07
申请号：EP21959310.0
申请日：2021-09-29
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , KOSHIKIYA, Yusuke , ISHIMARU, Takahiro
IPC分类号： H04B10/071
CPC分类号： H04B10/071
摘要： The present disclosure aims to reduce a strain of an observed waveform caused by a difference in proportional constant between responses of different optical frequencies of probe light resulting from vibration in a phase OTDR that uses different optical frequencies.
In order to achieve the above-described objective, the present disclosure relates to, in vibration measurement using a phase OTDR, including a compensation optical pulse with a predetermined compensation optical frequency different from an optical frequency in an optical pulse pair composed of optical pulses with different optical frequencies and making the optical pulse pair incident on a sensing fiber, calculating a phase value of the optical pulse pair based on a signal of the optical frequency from a scattered light signal based on the optical pulse pair and calculating a phase value of the compensation optical frequency based on a signal of the compensation optical frequency, plotting the phase values calculated from the scattered light signal on a two-dimensional, for each optical pulse pair plane, having the phase value of the compensation optical frequency represented by a horizontal axis and the phase value of the optical pulse pair represented by a vertical axis, obtaining a gradient and a vertical axis intercept of the approximate straight line calculated from the plotted data, and correcting the phase value of the optical pulse pair using the gradient and the vertical axis intercept.

7. 发明公开

EP4354100A1 VIBRATION MEASUREMENT DEVICE AND VIBRATION MEASUREMENT METHOD 审中-实审
公开(公告)号：EP4354100A1
公开(公告)日：2024-04-17
申请号：EP21945113.5
申请日：2021-06-09
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , KOSHIKIYA, Yusuke , IIDA, Hiroyuki , HONDA, Nazuki
IPC分类号： G01H9/00
CPC分类号： G01H9/00
摘要： The present disclosure aims to reduce crosstalk between different optical frequency components, and reduce erroneous detection of vibration and distortion of a vibrational waveform.
The present disclosure relates to a vibration measuring instrument that repeatedly injects a plurality of light pulses with different optical frequencies into an optical fiber, and performs distributed acoustic sensing-phase (DAS-P). In the vibration measuring instrument, light pulses having a waveform with a spectral side lobe smaller than a side lobe of a rectangular wave are used as the plurality of light pulses.

8. 发明公开

EP4300030A1 COHERENT LIGHT MEASURING DEVICE, AND OPTICAL LINE TEST SYSTEM AND METHOD 审中-实审
公开(公告)号：EP4300030A1
公开(公告)日：2024-01-03
申请号：EP21927934.6
申请日：2021-02-26
申请人： Nippon Telegraph And Telephone Corporation
发明人： IIDA, Daisuke , ENOMOTO, Yoshitaka , KITO, Chihiro , OKAMOTO, Tatsuya , KOSHIKIYA, Yusuke , WAKISAKA, Yoshifumi , HONDA, Nazuki
IPC分类号： G01B11/00
摘要： An object of the present disclosure is to enable testing of a long-distance optical fiber line and detecting of distances to a plurality of abnormal facilities.
The present disclosure is an optical line test system that detects a distribution of loss points of an optical line in a longitudinal direction, using a coherent light measurement device, applies vibration to facility disposed on a path of the optical line, detects a vibration point of the optical line in a longitudinal direction upon applying the vibration, using the coherent light measurement device, and identifies the loss point based on correspondence between the detected loss point and vibration point.

9. 发明公开

EP4170281A1 DISTORTION CHANGE MEASURING DEVICE AND DISTORTION CHANGE MEASURING METHOD 有权
公开(公告)号：EP4170281A1
公开(公告)日：2023-04-26
申请号：EP20941958.9
申请日：2020-06-22
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , ONO, Shingo , IIDA, Daisuke , OSHIDA, Hiroyuki
IPC分类号： G01B11/16 , G01D5/353 , G01L1/24
摘要： An object of the present disclosure is to measure, at a high sampling rate, a distribution of a vibration pattern applied to each core after being branched.
A strain change measurement apparatus according to the present disclosure inputs, at a reference time, first chirped pulsed light having a chirp having a frequency changing linearly with time to a measurement target optical fiber branched by a coupler, acquires a signal of first scattered light regarding the first chirped pulsed light, inputs, at each monitoring time, second chirped pulsed light having a chirp obtained by time axial inversion with respect to the first chirped pulsed light to the measurement target optical fiber to acquire a signal of second scattered light regarding the second chirped pulsed light, determines a shift amount allowing for maximization of a correlation between a waveform obtained by inverting the signal of the first scattered light around the time axis and further shifting and a waveform of the signal of the second scattered light, and uses the shift amount to calculate a change in strain amount in the measurement target optical fiber from the reference time to each monitoring time.

10. 发明公开

EP4047333A1 OPTICAL PULSE TESTING METHOD AND OPTICAL PULSE TESTING DEVICE 有权
公开(公告)号：EP4047333A1
公开(公告)日：2022-08-24
申请号：EP19949501.1
申请日：2019-10-17
申请人： Nippon Telegraph And Telephone Corporation
发明人： WAKISAKA, Yoshifumi , IIDA, Daisuke , OSHIDA, Hiroyuki
IPC分类号： G01H9/00
摘要： 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 (2nfvt), N = 4Zfv/v is satisfied when A is smaller than n/2 but N = 2Zfv/(ν·Arcsin (π/2A)) is satisfied when A is equal to or larger than n/2, where fv represents vibrational frequency, t represents time, Z represents a length of the measured optical fiber (a measurement distance), and v represents the speed of light inside the measured optical fiber.

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