JP3282753B2 - Automatic analysis method of optical line characteristics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pulse tester (OT).
Measuring the optical characteristics of the optical line using a DR), for automatic analysis of the measured data by using a computer, the optical line cable
Cable section loss, connection loss at connection point, and reflection amount,
In addition, the present invention relates to a method of obtaining and displaying these occurrence positions and failure occurrence positions.

[0002]

2. Description of the Related Art Conventionally, a technique relating to a method of automatically detecting a connection position or a failure position of an optical line has been disclosed (for example, Japanese Patent Application No. 62-238138: a method of detecting a defect position and an open end position of an optical fiber). reference). FIG. 13 shows a flowchart of the disclosed technology. This conventional method,
As shown in FIG. 13, it obtains a difference between a distance of ± Vτ / 4 around the point of interest OTDR waveform data position (step) determines whether the difference value is sharply changed stepwise (Step). When the position changes abruptly, a position farther by Vτ / 4 from the position Zs that changes stepwise is set as a defect position or an open end position (step).

If it is determined in the above step that the difference does not change abruptly, a position Zp at which the difference value becomes maximum or minimum within a distance section where the difference value becomes larger than a predetermined value is obtained (step), and Vτ / 4 is incident from the position Zp. The position near the end is defined as the defect position (step) .

A feature of the conventional method shown in FIG. 13 is that a difference between data having an appropriate interval is obtained from a measured data train of the optical pulse tester, and a data interval of a predetermined value or more is obtained in the difference data train. A singular point indicating a connection position or a failure position can be estimated from the maximum or minimum peak point.

[0005]

In the above-mentioned conventional singular point detection method, since the measurement data of the ordinary optical pulse tester has a worse signal-to-noise ratio (S / N) as the distance increases, the threshold value must be set. It is necessary to change for each cable unit and every distance, and there is a problem that the experiment operation or the program parameter change operation for that purpose becomes large.

In addition, when calculating connection loss and the like, the comparison between the analysis result and a database indicating the connection position in an actual optical line is manually performed, which is inefficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a cable section of an optical line based on measurement data obtained by measuring optical characteristics of the optical line.
It is an object of the present invention to provide an automatic analysis method of an optical line characteristic for obtaining an inter-loss, a connection loss at a connection point, an amount of reflection, a position where the loss and a position where the failure occurs, and displaying them.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0009]

In order to achieve the above object, the means (1) of the present invention measures the optical characteristics of an optical line using an optical pulse tester, and converts the obtained measurement data into a computer. In the automatic analysis method of optical line characteristics, which automatically finds and displays the connection loss, cable loss, reflection amount, their occurrence position and abnormality occurrence position of the optical line using A first processing step of measuring after setting appropriately according to the line, and converting the data obtained from the optical pulse tester into coordinate data ( Yi, Xi) using a vertical axis Y representing a loss and a horizontal axis X representing a distance. ), The second processing step of creating a cable data string (K, Xi) with the cable flag set to K, and the third processing of creating a differential coefficient string (dYi / dXi, Xi) at each coordinate. Stage The point at which the sign of the differential coefficient sequence changes from plus or zero to negative is defined as the peak position of the data, and the differential coefficient of each point of the pulse width section in the near end direction and the far end direction with respect to the peak position is referred to. dYi / dX
i, Xi) determine a near-end point (fs) and a far-end point (fe) within an error range as compared with the case of a cable, and determine the determined cable flag of the section (fs to fe). Let F be the cable data string (F, Xfs ~
fe), and when the data Y on the far end side from the Xfe is lower than the noise level, the Xfs is set to the line end Le. When the data Y is not lower than the noise level, the last Xfs is set to the noise level Le. A fifth processing step for determining the end of the line Le, and whether or not the end Le coincides with the line length in the database including a measurement error is determined. And a range (js-je) in which the differential coefficient of the differential coefficient sequence (dYi / dXi, Xi) changes more greatly than in the case of a cable.
The cable data string is (J,
Xjs to je), a seventh processing step of rewriting as
If the data for j e from the far end side of the near-end than the terminal Le obtained in also the fifth processing stage only below noise level, and an eighth processing steps to terminate Le of the Xjs line, terminating Le The ninth process is to judge whether or not the line length matches the line length in the database including the measurement error. If not, it is determined that the line has a fault, and the display of the fault and the display of the fault position at the end Le are performed. In the stage and the cable data sequence , the section where the cable flag is K is the cable section, the first position of each section where the cable flag is F is the connector connection position, and the first position of each section where the cable flag is J is fused. A tenth processing stage as a connection position, and an eleventh processing stage for calculating a loss in the cable section, a connection loss and a reflection amount at a connector connection position, a connection loss at a fusion splicing position, and a total line loss. And a twelfth processing stage for displaying the cable section loss, the connection loss, the reflection amount, the occurrence position, the total line loss, and the fault position obtained in the eleventh processing stage. .

[0010] Means (2) of the present invention, the (1) Warini seventh and eighth processing stage means, the point of the distance interval corresponding to the pulse width difference number sequence (.DELTA.YI, Xi)
A thirteenth processing step of generating a differential coefficient sequence (dΔYi / dXi, Xi) of the difference sequence obtained above, and a sign of the differential coefficient sequence changing from minus or zero to plus. And a fifteenth processing step for determining a position Xk that changes from plus or zero to minus,
Assuming that the cable flag in the section corresponding to the pulse width (pw) from k is J, the cable data string is (J, Xk to Xk +
a sixteenth processing Ridan floor to pw), from (Xk + pw)
When the data Y on the far end side is equal to or lower than the noise level,
If the line is closer to the end Le of the line determined in the processing stage, X
and a twentieth processing step in which k is the end Le of the line .

[0011] The means (3) of the present invention is characterized in that, during the ninth and tenth processing steps of the means (1) or (2), a connection point of a line previously prepared from an optical line design document is provided. The connection point information is read from the database using the database in which the information is registered, and the connection point data string (SF, SX) is read.
i) a seventeenth processing step for creating (SJ, SXi);
An allowable section is set from the equipment error for each connection point data, an eighteenth processing step for counting how many connection points found in the analysis fall within the allowable section of each connection point, and a case where the number of connection points is 0 In the section, the position of the connection point data string is used as a connection point, the section having one connection point uses the position of the connection point obtained by analysis, and the section having two or more connection points indicates the relationship between distance and loss. The connection point is narrowed down to one and the cable data sequence is rewritten
And a processing step.

[0012]

According to the above-described means, it is not necessary to make a determination based on the threshold value specified for the target line when detecting a singular point of the optical line, and a long-distance signal-to-noise ratio (S / N) becomes poor. Since it is not necessary to change the threshold setting for each cable and for each distance, analysis can be performed without depending on the line characteristics. Can be reduced. In addition, when a connection loss or the like is determined, the analysis can be performed by automatically associating the analysis result with a database indicating an actual connection position on the optical line.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing the configuration of Embodiment 1 of a system for implementing an automatic optical line characteristic analysis method according to the present invention.
1,2-2a, 2-2b, 2-2c are optical fibers, 3-1,
3-1a is a connector connection section, 2-2a and 3-2b are fusion connection sections, 4 is a data bus, 5 is a control / calculation section, 6 is a data processing section, 7 is a database, and 8 is a result display section. is there.

Next, the measurement principle of the optical pulse test section 1 will be described. When light is incident on the optical fiber, the light returning to the incident end from the middle of the optical fiber includes Fresnel reflected light due to connector connection points and a part of Rayleigh scattering occurring in the optical fiber to the optical fiber incident end. There is back scattered light back.

Here, when an optical pulse obtained by the pulse generator and the semiconductor laser is incident on the optical fiber, the backscattered light and Fresnel reflection generated in the optical fiber are proportional to the distance from the incident end to each generation position. After a time, it returns to the entrance end. The waveform of the returned light can be obtained by converting the returned light into an electric signal by a light receiving element. In the first embodiment, the vertical axis is logarithmically converted to the received light power received by the optical pulse test unit 1 and is displayed in decibels (dB). The horizontal axis indicates the distance.

FIGS. 2 and 3 are flowcharts showing the processing procedure of the optical line characteristic automatic analysis method according to the first embodiment.

A method for automatically analyzing the optical line characteristics according to the first embodiment will be described with reference to FIGS. 1, 2, and 3. FIG.

First, the control / calculation unit 5 optimizes the optical pulse test conditions as described below, gives an instruction to the optical pulse test unit 1 via the data bus 4, and executes the optical pulse test. This part corresponds to step S in FIG.
A-1 and SA-2.

The main parameters to be set are distance range, near-end mask, refractive index, optical attenuator, pulse width,
This is the averaging count. As for the distance range, the shortest range that can be measured in a section obtained by multiplying the distance on the database 7 by 1.15 considering the error is used. The optimum length of the near-end mask is experimentally determined in advance in accordance with the type of the connector connected to the optical pulse test unit 1. The refractive index is experimentally determined to be 1.48 so as to reduce the distance error at each wavelength.

The optical attenuator is set so that the start portion of the measurement waveform and the Fresnel reflection portion from the connector are not saturated. The pulse width is set to a small width in order to improve the resolution as much as possible within a range where the dynamic range of the entire optical pulse test is not less than the target line loss. The number of averaging is set as small as possible within a range where the dynamic range of the entire optical pulse test does not become lower than the target line loss. The optical attenuator Z, the pulse width Pw, and the number of averaging N are mutually related to the system dynamic range D. These relationships are as follows: the dynamic range of the optical pulse test unit is Do, the coupling loss with the line is C,
Assuming that the loss resolution of the optical pulse test waveform is X, it is expressed by Equation 1.

[0022]

[Equation 1] D = Do-C-5log (10X / 5-1) -2.5log (N / 218) +10
log (Pw / 1 μs) -Z The system dynamic range D corresponds to the measurable distance. Assuming that Do, C, D, and X are constant, each parameter can be optimized by calculating the relationship between the optical attenuator Z, the pulse width Pw, and the number of averaging N using Equation 1.

Next, the data measured by the optical pulse test section 1 is analyzed by the data processing section 6. The operation procedure is from step SA-3 to step SA-14. Hereinafter, this procedure will be described.

First, optical pulse waveform data (Yi, Xi)
Is taken into the data processing unit 6 (SA-3). Where Y
i is the light receiving level (dB), and Xi is the point corresponding to the distance.
It is. The actual distance is the distance ΔL of one point to Xi.
Multiplied by Optical pulse test of the optical line shown in Fig. 1
FIG. 4 shows an example of waveform measurement. Data is a point but usually Δ
Since L is as small as several meters, it is seen as an upper line on the display. same
In FIG. 4, 2-2a, 2-2b, 2-2c and 2-2d are cables.
Sections, 3-2a and 3-2b are fusion splicing points, sectionslTwol
3, sectionl6 ~l7 is a fusion splicing point section, 3-1a is a connector
Kuta connection point, sectionl4 ~l5 is a connector connection point section,l
Reference numeral 8 denotes a terminal point of the track, which is a connector connection point and a line end.
Fresnel reflection occurs at the end point.

The correction of the near end mask section will be described with reference to FIG. Since the near end mask section is determined by the pulse width and the distance range, a predetermined position is set at the far end beyond the near end mask width.
From the mask1, the slope is determined for each section mask2 using the least squares method, and a position mask3 where the slope of the section mask2 exceeds the error range of the tilt of the cable is determined. And cable section ma
The slope mask4 of the section from sk1 to mask3 is obtained by the least square method, and the data string (Yi, Xi) is corrected with the section of mask1 from the incident end as the cable section of the slope mask4. FIG. 6 shows an example of the corrected waveform.

Next, a cable data string (K, Xi) is created with the cable flags of all sections set to K (step SA-4). The cable data string indicates the state of the equipment at the point indicated by Xi. This step SA-
In 4, all sections are set as cable sections as an initial setting by using K as a cable flag indicating a cable section.

Next, the differential coefficient d at each point Xi
Yi / dXi is calculated and a differential coefficient sequence (dYi / dXi, Xi)
Is created (step SA-5). Where the derivative d
Yi / dXi is obtained as a slope by calculating a regression line using points before and after Xi. Next, dYi
/ Section codes dXi is from plus or zero and the reference points vary significantly to the noise level over the minus Xf
Find s and Xfe.

This section includes a series of differential coefficients (dYi / dXi,
The derivative (dYi / dXi) of the point in the pulse width section in the near end direction and the far end direction with respect to the point where Xi) changes from plus or zero to minus is the derivative (dYi) of the cable section. / DXi), the point at the near end which is within the error range compared to Xfs is Xfs, and the point at the far end is X
It shall be the fe. This is performed for all data sections and Xfs
Find n and Xfen. Here, n = 1, 2,..., And n indicates the order of the section from the optical line start position (step SA-6).

Further, the Fresnel reflection section Xf obtained above is obtained.
The cable flags of sn to Xfen are set to F indicating the Fresnel reflection section, and the cable data string of the section is (F, Xf
sn−Xfen) (step SA-7).
This section corresponds to the Fresnel reflection sections l 4 to l in FIG.
5 corresponds to the interval l. 8 to l 9. Therefore, the Fresnel reflection section can be detected in step SA-7.

Next, when there is a section where the data Y on the far end side of Xfsn is lower than the noise level, the Xfsn is set to the end Le of the line. When there is no section lower than the noise level, the last Xfsn is set to the line end. The end is set to Le (step SA-8). Next, it is determined whether the obtained position of the end Le of the line matches the line length on the database including the measurement error (step SA-9). If they do not match, it is determined that there is a fault in the line, and a display of the fault and a display indicating that the fault position is at the end Le are terminated (step SA-10). If they match, the process proceeds to Step SA-11.

In step SA-11, dYi / dXi
Is determined in all data sections where the cable flag is K, the cable flag of the section determined above is set to J indicating the fusion section, and the cable data of the section is set to (J , Xjsm to Xjem)
Rewrite as. However, m = 1, 2,..., And m indicates the order of the section from the optical line start position. This interval is 4, fusion splice section l. 2 to l
3, corresponds to the interval l. 6 to l 7. Therefore, the fusion splicing section can be detected in this step.

Next, there is a section where the data Y on the far end side from Xfsn is equal to or lower than the noise level.
If m is closer to the end Le than the end Le obtained in step SA-8 in FIG. 2, Xjsm is set as the end Le of the line (step S8).
A-12). Next, it is determined whether or not the obtained end Le of the line matches the line length in the database including a measurement error in advance (step SA-13). If not, it is determined that the line has a failure. The display of the failure and the display of the failure position at the end Le are terminated (step SA-).
14). If they match, the process proceeds to Step SA-15.

In step SA-15, the section where the cable flag is K is the cable section, the section of F is the Fresnel reflection section, the section of J is the fusion connection section, the start point of the section of F is the connector connection position, and the section of J Is the fusion splicing position.

Next, in step SA-16, using the connection point positions obtained in step SA-15, cable section loss, connector and fusion splice loss, connector reflection amount,
Find the total line loss. The method will be described below. First, the section loss will be described with reference to FIG. In the section between the connection point li (l is a lowercase letter of L) and li + 1, the sections li 'and li ' +
A straight line approximation by the least squares method is performed using the waveform data between 1 . If the resulting equation is y = ax + b, the section loss (Si-Si + 1) is obtained by (a * li-a * li + 1).

Next, connection loss will be described with reference to FIG. Light reception level at the center of each cable section {Sm (i i +
1), Sm (i + 2 i + 3) ,...} And the section loss value {(Si−Si + 1),
(Si + 2−Si + 3),...}} To determine the connection loss Slose. From these, the following relational expression 2 holds from FIG.

[0036]

Sm (i i + 1) − (Smi + 2 i + 3) = (Si−Si + 1) / 2 + Sp + (Si + 2−Si + 3) / 2

[0037]

## EQU3 ## Connection loss Slose = Sm (i i + 1) − Sm (i + 2 i + 3) − (Si−Si + 1) / 2− (Si + 2−Si + 3) / 2 By using Equation 3, it is possible to reduce the influence of variations in waveform data around the connection point.

Next, the reflection amount of the connector will be described with reference to FIG. The light receiving level Sci of the approximate straight line of the cable section at the connector connection position lci and the peak value Sfi of Fresnel reflection at the connector connection position lci
And the level difference (Sfi-Sci) is determined as the reflection amount of the connector. Further, the total line loss is obtained by adding all the cable section loss, connector connection loss, and fusion splice loss determined so far.

Finally, at step SA-17, the analysis results show the loss of each cable section, the total line loss, the connector connection loss, the fusion splice loss, the amount of reflection, and the position of the connection point, and terminate the analysis.

(Embodiment 2) In Embodiment 2 of the present invention, the data measured by the optical pulse test unit 1 of Embodiment 1 is analyzed by the data processing unit 6, and Step SA in the flow shown in FIGS. -11 and SA-
12 is obtained by replacing Steps SB-1 to SB-5 in the new data analysis flow shown in FIG.

The procedure of the analysis according to the second embodiment of the present invention is as follows.
After step SA-9 in FIG. 2 has been completed, it proceeds non to step SB-1 in FIG. 11. Hereinafter, steps SB-1 to SB-
5 will be described. Steps SA- 1 to SA-10 have been described in the first embodiment, and a description thereof will be omitted.

After the completion of step SA-9, the process proceeds to step SB-1 shown in FIG. 11, in which a difference between the data Y for each point is obtained at a distance interval corresponding to the pulse width (pw).
A difference sequence (ΔYi, Xi) is created. Next, determine the differential coefficient dΔYi / dXi of the difference between fractional column, differential coefficient sequence (dΔ
Yi / dXi, Xi). (Step SB-
2). FIG. 7 shows the obtained difference waveform.

Next, the sign of dΔYi / dXi is minus.
Or from zero to plus or from plus or zero to my
Cave the point where the change to the eggplant greatly exceeds the noise level
(Xkl, Xi)
And Where l = 1, 2,... (L is a small letter of L)
What is the section from the optical line start position
Indicates l (step SB-3). X
cable for the section (pw) corresponding to the pulse width from kl
The data string is (J, Xkl to Xk + pwl) (SB
-4). This section is a fusion section (lTwol
3), (l6 ~lThis corresponds to 7). So this step
In SB-3, the fusion splicing section can be detected.

Next, data Y Xk l by <br/> Ri far end in the cable data string even only at the noise level below Xkl
Is closer to the end Le than obtained in step SA-8,
Xkl is set as the end Le of the line (step SB-5).
After step SB-5 ends, step S5 shown in FIG.
Proceed to A-13. The processing after step SA-13 is the same as in the first embodiment.

In the second embodiment, in the fusion splicing detection, the fusion splicing section is detected by using a differential coefficient sequence of a differential function sequence having a difference interval corresponding to a pulse width. Compared with this, it is less likely to be affected by noise and can be detected with high accuracy.

(Embodiment 3) The third embodiment of the present invention relates to a fusion line section and a Fresnel reflection section obtained in the first and second embodiments and a line formed from a design document at the time of construction of the optical line. Using the database, step S in the flow shown in FIG.
It is added between A-13 and step SA-15. Hereinafter, description will be made with reference to FIG.

The connection point information is read from the database,
Connection point data string (SF, SXifn) (SJ, SXij
n). Where fn = 1, 2,..., Jn =
1, 2,..., Fn indicates the number of the connector connection point when viewed from the optical line start position, and jn indicates the number of the fusion connection point. This SF is a cable flag indicating the connector connection, and indicates that the cable is located at the point of SXi. SJ is a cable flag indicating fusion splicing, indicating that the cable is located at the point of SXi (SC-
1).

Next, an allowable section is set for each connection point data based on the error of the equipment, and the number of connection points determined by the analysis is included in the allowable section of each connection point. The allowable range is determined by the reliability of the equipment data (step SC-
2).

Next, the process proceeds to step SC-3, and in a section where the number of connection points obtained by the analysis is 0, the cable data string is rewritten using the position of the connection point data as a connection point. In step SC-4, in the section where the number of connection points determined by the analysis is one, the cable data string is rewritten using the determined connection points. Next, proceeding to step SC-5, in the section where the number of connection points obtained by the analysis is 2 or more, the connection points are narrowed down to one using the relationship between distance and loss, and the other parts are affected by the influence of cable noise. Assuming that an error has occurred, rewrite the cable data string. Note that the relationship between the distance and the loss is expressed by using Equation 4, and the determined connection point at which A becomes the maximum is used.

[0050]

A = (| connection position on facility data−calculated connection point position | × B) × (| calculated connection point loss−C | × D) B, C, D used in Expression 4 each factor can be determined from the measured in a laboratory or the like data.

In the third embodiment, by using the line database, it is possible to remove a connection point which is erroneously regarded as a connection point due to the influence of noise or the like.

As described above, the invention made by the present inventor
Although the present invention has been described in detail with reference to the embodiment, the present invention is not limited to the embodiment, and it is needless to say that various changes can be made without departing from the scope of the invention.

[0053]

As described above, according to the present invention, since the change of the sign of the differential coefficient is used for detecting the connection point, the threshold value is set for each cable and each distance as in the conventional method. Since there is no need to change, it is possible to reduce the number of experiments for setting the threshold value or the number of operations for changing the parameters of the program.

Since the number of parameter settings is small, the analysis can be speeded up.

Further, by automatically associating the analysis result with the database indicating the actual connection position on the optical path and performing the analysis, the operation of the analysis can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of a first embodiment of a system for implementing an automatic optical line characteristic analysis method according to the present invention;

FIG. 2 is a flowchart showing a processing procedure of an automatic optical line characteristic analysis method according to the first embodiment;

FIG. 3 is a continuation of the flowchart shown in FIG. 2;

FIG. 4 is a diagram showing an example of an optical pulse test waveform according to the first embodiment;

FIG. 5 is a diagram for explaining correction between near-end masks according to the first embodiment;

FIG. 6 is a diagram showing an example of an optical pulse test waveform in which the distance between the near-end masks is corrected according to the first embodiment;

FIG. 7 is a view showing an example of a difference waveform of the optical pulse test waveform according to the second embodiment;

FIG. 8 is an explanatory diagram for calculating an interval loss according to the first embodiment;

FIG. 9 is an explanatory diagram for calculating an interval loss according to the first embodiment;

FIG. 10 is an explanatory diagram for calculating a reflection amount of the connector according to the present embodiment;

FIG. 11 is a flowchart showing a processing procedure of an optical line characteristic automatic analysis method according to the second embodiment of the present invention;

FIG. 12 is a flowchart showing a processing procedure of an optical line characteristic automatic analysis method according to the third embodiment of the present invention;

FIG. 13 is a flowchart showing a conventional connection point detection procedure.

[Explanation of symbols]

1. Optical pulse test section, 2-1 2-2a, 2-2b, 2-2
c, 2-2d: optical fiber, 3-1; 3-1a: connector connection section, 2-2a, 2-2b: fusion splicing section, 4: data bus, 5: control / calculation section, 6: data processing Part, 7 ... Database, 8 ... Display part of result.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yahei Oyamada 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Naoyuki Atobe 1-1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Inside Telegraph and Telephone Corporation (72) Takashi Nagasaki 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-64-79637 (JP, A) JP-A-2- 223840 (JP, A) JP-A-4-83140 (JP, A) JP-A-4-211204 (JP, A) JP-A-2-130447 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 11/00-11/08

Claims (3)

(57) [Claims] An optical pulse tester is used to measure the optical characteristics of an optical line, and the obtained measurement data is automatically connected to a computer using a computer, and the connection loss, cable loss, reflection amount of the optical line, and the occurrence thereof are measured. A method for automatically analyzing the characteristics of an optical line for obtaining and displaying a position and an occurrence position of an abnormality, a first processing step of appropriately setting measurement conditions of an optical pulse tester in accordance with a target line and then performing measurement; The data obtained from the container are represented by coordinate data ( Yi, Xi ) on the vertical axis Y representing the loss and the horizontal axis X representing the distance.
A second processing step of creating a cable data string (K, Xi) with the cable flag set to K and a third processing step of creating a differential coefficient string (dYi / dXi, Xi) at each coordinate And a point at which the sign of the differential coefficient sequence changes from plus or zero to negative is defined as the peak position of the data, and the differential coefficient of each point of the pulse width section in the near end direction and the far end direction with reference to the peak position. The point (fs) of the near end portion and the point (fe) of the far end portion where (dYi / dXi, Xi) are within the error range compared with the cable case are obtained, and the obtained section (fs to fe) is obtained. cable data sequence as F cable flag (F, Xfs~fe) a fourth processing step of rewriting and, if the data Y of the far-end side of the Xfe becomes noise level or less, the Xf Is the end Le of the line, and if the noise level does not fall below the fifth line, the fifth processing step of setting the last Xfs to the end Le of the line, and whether the end Le matches the line length on the database including the measurement error If they do not match, it is determined that there is a fault on the track, and the fault indication and fault location are set to the end L
e, a cable data sequence where J is a cable flag in a range (js-je) where the differential coefficient of the differential coefficient sequence (dYi / dXi, Xi) changes more greatly than in the case of a cable. To (J, Xj
a seventh process step of rewriting the S～je), data of the Xj e from the far end is the case of the near-end than the terminal Le also obtained by the fifth processing stage only the noise level below the Xjs lines Eighth processing step of terminating Le, and determining whether or not the terminating Le matches the line length on the database including a measurement error. If not, it is determined that the line has a fault, and the display of the fault and Failure position is at the end Le
, A cable section where the cable flag is K in the cable data string , the first position of each section where the cable flag is F is the connector connection position, and the cable flag is J. A tenth processing step in which the first position of each section is a fusion splicing position; and a step of calculating the loss of the cable section, the connection loss and the amount of reflection at the connector connection position, the splice loss at the fusion splicing position, and the total line loss. An eleventh processing stage, and a twelfth processing stage for displaying the cable section loss, the connection loss, the reflection amount, the occurrence position, the total line loss, and the fault position obtained in the eleventh processing stage. Automatic analysis method of characteristic optical line characteristics. Wherein Warini generations of the seventh and processing steps of the eighth, the thirteenth processing step of creating a difference number sequence of points of the distance interval corresponding to the pulse width (.DELTA.YI, Xi), the difference which has been determined by the A sequence of differential coefficients (dΔYi / dX
i, Xi), a fifteenth processing step of finding a position Xk at which the sign of the differential coefficient sequence changes from minus or zero to plus and from plus or zero to minus, and from the Xk Assuming that the cable flag in the section corresponding to the pulse width (pw) is J, the cable data string is (J, Xk to
Xk + pw), and a (Xk + p)
w) The data Y on the far end side is below the noise level and
The field near the end Le of the line determined in the fifth processing step
A twentieth processing step in which Xk is the end Le of the line;
The method for automatically analyzing optical line characteristics according to claim 1, wherein: 3. The method according to claim 1, wherein during the ninth and tenth processing steps,
The connection point information is read from the database using a database in which the connection point information of the line prepared in advance from the design document of the optical line is registered, and the connection point data sequence (SF, SX) is read.
i) A seventeenth processing step for creating (SJ, SXi), and an allowable section is set for each connection point data based on the error of the equipment, and how many connection points obtained by the analysis fall into the allowable section of each connection point. In the eighteenth processing step for counting the number of connection points, in the section where the number of connection points is 0, the position of the connection point data string is used as the connection point, and in the section where the number of connection points is 1, the position of the connection point obtained by analysis is used. , the number of connection points is a connection point aperture to one with two or more section distance and loss of relations, according to claim 1 or claim characterized in that it comprises a processing stage of the 19 to rewrite the cable data sequence Item 3. An automatic analysis method for optical line characteristics according to Item 2 .