Optical cable testing method, system, optical time domain reflection equipment and medium based on OTDR
By using the maximum test pulse width of maximum gain in optical cable testing, correcting event points and fitting cable length, the problem of measuring distance and event resolution balance is solved, and more accurate cable testing is achieved.
Patent Information
- Application Number
- CN202411534439.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2044-10-31
AI Technical Summary
In optical cable testing, it is difficult to balance the measurement distance and event resolution. The prior art requires artificially setting the appropriate test pulse width to improve measurement accuracy, but this will lead to a decrease in event resolution.
Measurements are made by satisfying the maximum test pulse width of the cable maximum gain, obtaining test curve data, correcting the event start and end points, fitting the cable length, and obtaining the minimum test pulse width for more accurate cable testing.
It achieves rapid and efficient acquisition of the test distance and minimum test pulse width of the optical cable, improves the accuracy and efficiency of the optical cable test, and can accurately locate power loss events and integrate signal change events.
Smart Images
Figure CN119043676B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of optical cable testing, and more specifically, to an optical cable testing method, system, optical time domain reflection equipment and medium based on OTDR. Background Art
[0002] Distributed fiber optic detection equipment can test the length and line quality of optical cables. However, during the test, if you want to increase the measurement distance, you must select a larger test pulse width, which will cause a decrease in event resolution. Therefore, it is difficult to achieve a balance between the two parameters of measurement distance and measured event resolution. In actual use, it is necessary to set appropriate test pulse width, test distance and other parameters to obtain the maximum test accuracy on the basis of meeting the test length requirements. Summary of the invention
[0003] The present invention aims to overcome at least one defect of the above-mentioned prior art and provide an OTDR-based optical cable testing method, system, optical time domain reflectometry device and medium, which are used to quickly and effectively obtain a suitable test pulse width and test distance to achieve more accurate optical cable testing.
[0004] The technical solution adopted by the present invention is:
[0005] In a first aspect, the present invention provides an optical cable testing method based on OTDR, the testing method comprising:
[0006] The optical cable is measured by a maximum test pulse width that satisfies the maximum gain of the optical cable to obtain corresponding test curve data; the test curve data is used to reflect the length-signal condition of the optical cable;
[0007] Acquire an event start point and an event end point of a signal change event according to the test curve data, and correct the event start point to obtain a corresponding corrected event start point;
[0008] Acquire the corresponding normal optical cable segment in the test curve data according to the correction event starting point and event end point;
[0009] Fitting the test curve data to obtain the optical cable length of the optical cable;
[0010] Acquire a test distance of the optical cable according to the length of the optical cable;
[0011] The minimum test pulse width of the optical cable test is obtained according to the normal optical cable segment.
[0012] By directly adopting the maximum test pulse width that can meet the maximum gain of the optical cable to measure and obtain the test curve data, the obtained test curve data can reflect the measurement conditions of the optical cable under the maximum gain, including various event points on the optical cable, the length of the optical cable and the overall loss of the optical cable, etc. Then, various parameter information of the optical cable used for testing can be quickly and effectively obtained based on the various information on the optical cable obtained from the test curve data.
[0013] Furthermore, the obtaining of the event start point and event end point of the signal change event according to the test curve data specifically includes:
[0014] In the test curve data, a curve segment whose signal strength decreases by more than a preset threshold is obtained;
[0015] The starting point of the curve segment is used as the event starting point of the signal change event, and the end point of the curve segment is used as the event end point of the signal change event.
[0016] The decrease amplitude refers to the change in the signal strength per unit distance. If the decrease amplitude of the signal strength exceeds a preset threshold, it indicates that a power loss event has occurred at that position of the optical cable. By calculating the decrease amplitude of the signal strength, the location points of each power loss event on the optical cable can be accurately located.
[0017] Further, the correcting the event starting point to obtain a corresponding corrected event starting point specifically includes:
[0018] In the test curve data, a curve segment with the event starting point as the end point and a continuously rising signal strength is obtained;
[0019] Using the acquired starting point of the curve segment as the starting point of the correction event;
[0020] If the signal strength at the start point of the calibration event is the same as the signal strength at the event end point of the corresponding signal change event, then the signal change event is removed;
[0021] If the distance between the event end point of one signal change event and the correction event starting point of the subsequent signal change event does not exceed the preset distance, the two signal change events are merged into one signal change event, and the correction event starting point of the previous signal change event before the merger is used as the correction event starting point of the merged signal change event, and the event end point of the subsequent signal change event after the merger is used as the end point of the merged signal change event.
[0022] By correcting the starting point of the event, the coverage of the event can be adjusted, and then some events with inclusion relationship can be integrated. On the one hand, it can facilitate the viewing and analysis of the events. On the other hand, after the events are integrated, the area of normal loss in the test curve data can be reduced, which is convenient for subsequent calculations.
[0023] Further, fitting the test curve data to obtain the optical cable length of the optical cable specifically includes:
[0024] Fitting the test curve data;
[0025] The length of the optical cable corresponding to the last starting point of the event is obtained from the fitted test curve data as the length of the optical cable.
[0026] The last event starting point represents the last event point on the optical cable where loss occurs. This loss is usually the loss caused by the end of the optical cable being connected to the device. Therefore, by obtaining the last event starting point, the optical cable length of the optical cable can be effectively obtained.
[0027] Further, obtaining a normal optical cable segment in the test curve data according to the correction event start point and the event end point specifically includes:
[0028] Taking the curve segment between two consecutive signal change events in the test curve data as the normal optical cable segment, and obtaining a plurality of the normal optical cable segments in the test curve data;
[0029] The normal optical cable section takes the event end point of the first signal change event of the two consecutive signal change events as the starting point, and takes the correction event starting point of the next signal change event as the end point.
[0030] Further, the obtaining of the minimum test pulse width of the optical cable test according to the normal optical cable segment specifically includes:
[0031] The difference in signal strength between the starting point of the first normal optical cable segment and the end point of the last normal optical cable segment in the fitted test curve data is used as the dynamic range of the optical cable test, and the minimum test pulse width of the optical cable test is obtained according to the dynamic range of the optical cable.
[0032] The starting point of the correction event after correction is an abnormal power rising point, the starting point of the last correction event corresponds to the lowest point of the signal strength on the optical cable, and the starting point of the initial normal optical cable segment corresponds to the highest point of the signal strength on the optical cable. By calculating the difference in signal strength between the starting point of the initial normal optical cable segment and the starting point of the last correction event, the power attenuation of the optical cable can be effectively obtained, and then the minimum test pulse width of the optical cable can be effectively obtained.
[0033] Further, the obtaining of the minimum test pulse width of the optical cable test according to the dynamic range of the optical cable specifically includes:
[0034] The dynamic range is added with a preset margin to obtain the corrected dynamic range as the minimum test pulse width.
[0035] A certain margin is added to the dynamic range for correction, so as to ensure that the corrected dynamic range can better realize the measurement of the optical cable and fully display the measurement result.
[0036] In a second aspect of the present invention, there is also provided an optical cable testing system based on OTDR, the testing system comprising:
[0037] A test curve acquisition module, used to measure the optical cable by a maximum test pulse width that satisfies the maximum gain of the optical cable, and acquire corresponding test curve data; the test curve data is used to reflect the length-signal condition of the optical cable;
[0038] An event point acquisition module, used for acquiring an event start point and an event end point of a signal change event according to the test curve data, and correcting the event start point to obtain a corresponding corrected event start point;
[0039] An optical cable segment acquisition module, used for acquiring a normal optical cable segment corresponding to the test curve data according to the correction event start point and event end point;
[0040] An optical cable fitting module, used for fitting the test curve data to obtain the optical cable length of the optical cable;
[0041] A test distance acquisition module, used to acquire the test distance of the optical cable according to the length of the optical cable;
[0042] The test pulse width acquisition module is used to acquire the minimum test pulse width of the optical cable test according to the normal optical cable segment.
[0043] In a third aspect, the present invention further provides an optical time domain reflectometer, comprising a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the OTDR-based optical cable testing method described in the first aspect.
[0044] According to a fourth aspect of the present invention, a computer storage medium is provided, on which a computer readable program is stored. When the computer readable program is executed, the optical cable testing method based on OTDR described in the first aspect is implemented.
[0045] Compared with the prior art, the present invention has the following beneficial effects:
[0046] The present invention directly adopts the maximum test pulse width that can meet the maximum gain of the optical cable to measure and obtain the test curve data. The obtained test curve data can reflect the measurement situation of the optical cable under the maximum gain, and then the optical cable information such as the event starting point, event end point, calibration event point and normal optical cable section in the test curve data can be obtained. Then, according to various optical cable information on the optical cable obtained by the test curve data, the test distance and the minimum test pulse width used for testing the optical cable can be quickly and effectively obtained. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Figure 1 The figure is a flow chart of the steps of the testing method of the present invention.
[0048] Figure 2 It is a schematic diagram of the test curve data of the present invention.
[0049] Figure 3 It is a system structure diagram of the test system of the present invention.
[0050] Figure 4 This is a device structure diagram of the optical time domain reflectometer of the present invention.
[0051] The accompanying drawings are marked with: test curve acquisition module 11, event point acquisition module 12, optical cable segment acquisition module 13, optical cable fitting module 14, test distance acquisition module 15, test pulse width acquisition module 16, memory 21, processor 22, bus 23, and communication interface 24. DETAILED DESCRIPTION
[0052] The drawings of the present invention are only for illustrative purposes and should not be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.
[0053] Example 1
[0054] With the continuous development of optical fiber communication technology, the laying of optical cables has begun to increase gradually. After the laying of optical cables, before they are actually put into use, the performance of the optical cables needs to be tested to detect and eliminate faults. In the prior art, the performance of optical cables is usually measured by an optical time domain reflectometer (OTDR), which usually injects a high-power laser or light pulse at one end of the optical cable and receives the reflected signal through the same side. However, when measuring, it is necessary to manually set appropriate measurement parameters. In the process of testing, in order to increase the measured distance, it is necessary to select a larger test pulse width. However, as the test pulse width increases, the detected event resolution will decrease accordingly. Therefore, it is difficult to achieve a balance between the two parameter items of the measured distance and the measured event resolution. In the actual test process, it is necessary to set appropriate test parameters such as test pulse width and test distance to improve the test accuracy on the basis of meeting the test length requirements.
[0055] In order to effectively solve the problems existing in the above-mentioned prior art, Figure 1 As shown, this embodiment provides an optical cable testing method based on OTDR, and the testing method includes:
[0056] S1: measuring the optical cable by a maximum test pulse width that satisfies the maximum gain of the optical cable, and obtaining corresponding test curve data;
[0057] In this embodiment, specifically, the optical cable is measured by an optical time domain reflectometer, the optical time domain reflectometer is connected to the optical cable to be tested, and then light with a maximum test pulse width that can meet the maximum gain of the optical cable is emitted from one end of the optical cable, and a corresponding reflection signal is received at the other end to form the test curve data, and the test curve data is displayed by a display device of the optical time domain reflectometer.
[0058] like Figure 2 As shown, the test curve data represents the relationship between the measured optical cable length and signal strength, wherein the horizontal axis represents the measured length of the optical cable, and the vertical axis represents the signal strength at the length position of the corresponding optical cable, so the test curve data can reflect the signal conditions of various position points on the optical cable. In this embodiment, light of the maximum test pulse width with maximum gain is injected into the optical cable, and under the action of the light of the maximum test pulse width, the corresponding test curve data is obtained, which effectively reflects the effective test distance of the optical cable and the power attenuation of the optical cable, so that the test parameters of the optical cable can be set conveniently and quickly.
[0059] S2: acquiring an event start point and an event end point of a signal change event according to the test curve data, and correcting the event start point to obtain a corresponding corrected event start point;
[0060] In this embodiment, if Figure 2 As shown, the test curve data shows an overall downward trend. This is because light will be lost during transmission in the optical cable, resulting in the signal strength of the light gradually decreasing as the length of the optical cable increases.
[0061] Further, from Figure 2 It can also be seen that in the test curve data, the signal strength at several positions suddenly dropped drastically and then stabilized, which means that signal change events occurred at these positions of the optical cable. The signal change events may include reflection events / signal attenuation events, which may be caused by external environmental factors, such as bending of the optical cable, damage to the optical cable, or some conventional factors, such as attenuation at the interface caused by the fusion of the optical cable.
[0062] Therefore, by obtaining the event start point and event end point of the signal change event, it is helpful to identify the signal change event, judge which ones are caused by conventional factors and which ones are caused by external environmental factors, and then realize the maintenance of the optical cable.
[0063] Specifically, in this embodiment, obtaining the event start point and the event end point may specifically include:
[0064] In the test curve data, a curve segment in which the decline of the signal strength exceeds a preset threshold is obtained; the decline refers to the amount of change of the signal strength under a unit distance change. When the decline of the signal strength exceeds the preset threshold, it indicates that the signal strength has dropped drastically, and it can be determined that an event causing signal attenuation loss has occurred here;
[0065] The starting point of the curve segment is used as the event starting point of the signal change event, and the end point of the curve segment is used as the event end point of the signal change event.
[0066] The event starting point obtained by the above method can only include some signal change events. Some signals will suddenly rise before attenuation occurs. When reaching a certain height, there will be a cliff-like drop. Therefore, the event starting point and the corresponding event end point of the signal change event calculated simply by the above method cannot completely cover the entire range of the signal change event. In addition, in the actual measurement process, outside the length range of the optical cable, after the signal strength has dropped to 0, there will still be a part of the signal strength that rises and falls rapidly. This part of the signal strength change is caused by the interference in the optical cable, and this part of the interference needs to be eliminated. At the same time, the signal change events obtained in the test curve data are too dense, and it is not convenient to observe the signal change events. Therefore, it is necessary to calibrate the event starting point. Specifically, the calibration specifically includes:
[0067] In the test curve data, a curve segment with the event starting point as the end point and a continuously rising signal strength is obtained;
[0068] Using the acquired starting point of the curve segment as the starting point of the correction event;
[0069] If the signal strength at the start point of the calibration event is the same as the signal strength at the event end point of the corresponding signal change event, then the signal change event is removed;
[0070] This step is mainly to eliminate interference signal changes outside the length of the optical cable. Because on the optical cable, the signal strength is in a state of continuous attenuation. Even if the signal strength is increased within a certain range after reflection, for the corrected signal change event, the signal strength of the event endpoints before and after the corrected event must be smaller than the signal strength of the correction event endpoint. Therefore, interference can be determined and removed in this way.
[0071] If the distance between the event end point of one signal change event and the correction event starting point of the subsequent signal change event does not exceed the preset distance, the two signal change events are merged into one signal change event, and the correction event starting point of the previous signal change event before the merger is used as the correction event starting point of the merged signal change event, and the event end point of the subsequent signal change event after the merger is used as the end point of the merged signal change event.
[0072] This step is mainly to merge all the signal change events that are too close in distance. In actual scenarios, since the event that affects the signal strength has a range of effects on the optical cable, it usually presents a change in signal strength within a certain length range of the optical cable, that is, if multiple signal change events are too close, it can be said that these signal change events are actually the same signal change event. Therefore, merging the signal change events that are close in distance can integrate the same signal change events, and it can also facilitate the observation of the test curve data.
[0073] The correction event starting point obtained through correction has a larger coverage range than the event starting point before correction, and can include more of the signal change events. At the same time, by adjusting the starting point of the signal change event, some of the signal change events with similar properties can be integrated, thereby facilitating the subsequent calculation of normal optical cable segments and the fitting of the test curve data.
[0074] S3: acquiring a corresponding normal optical cable segment in the test curve data according to the correction event starting point and the event end point;
[0075] Specifically, in this embodiment, obtaining the normal optical cable segment may include:
[0076] Taking the curve segment between two consecutive signal change events in the test curve data as the normal optical cable segment, and obtaining a plurality of the normal optical cable segments in the test curve data;
[0077] The normal optical cable section takes the event end point of the first signal change event of the two consecutive signal change events as the starting point, and takes the correction event starting point of the next signal change event as the end point.
[0078] As mentioned above and see Figure 2 The normal optical cable segment represents an area of normal signal strength loss in the test curve data, so the curve segment where normal loss occurs between each signal change event is taken as the normal optical cable segment. Multiple normal optical cable segments can be obtained in the test curve data, and the normal optical cable segment and the signal change event represent the actual length of the optical cable.
[0079] Among them, the starting point of the first normal optical cable segment is the starting point of the optical cable, that is, the port connected to the optical time domain reflectometer. Since it is connected to the optical time domain reflectometer, a reflection event occurs at the starting point; correspondingly, the end point of the last normal optical cable segment is the end of the optical cable.
[0080] S4: Fitting the test curve data to obtain the optical cable length of the optical cable;
[0081] In this embodiment, the acquisition of the optical cable length of the optical cable can be performed by acquiring the length of the optical cable corresponding to the last event starting point in the fitted test curve data as the optical cable length of the optical cable. The fitting of the test curve data can be performed by fitting the average value of the signal strength of the content within a certain distance range in the test curve data, and a smooth fitted test curve data is obtained by fitting.
[0082] The test curve data after fitting includes all the normal optical cable segments and signal change events, so the coverage of the test curve data after fitting includes the optical cable length of the optical cable. At the end of the optical cable, since the optical cable is connected to the optical cable equipment, signal reflection will occur at the end of the optical cable, that is, a reflection event, and the signal strength will drop to 0. Therefore, the position of the starting point of the last event in the test curve data after fitting is the cable length of the optical cable, which can quickly realize the acquisition of the optical cable length.
[0083] S5: Obtaining a test distance of the optical cable according to the length of the optical cable;
[0084] After obtaining the cable length of the optical cable, it is necessary to further obtain the test distance for the optical cable test. The test distance represents the display range of the test curve data on the display device of the optical time domain reflectometer. In order to be able to display better, in this embodiment, the test distance can be set to 1.5-2 times the cable length of the optical cable. The test curve data set in this way can better and more completely display the relationship between the optical cable length and the signal strength, and when it is necessary to add optical cables in the future, it is convenient to carry out optical cable testing and reposition the test distance of the optical cable.
[0085] S6: Acquire a minimum test pulse width for the optical cable test according to the normal optical cable segment.
[0086] As described above, the starting point of the first normal optical cable segment corresponds to the front end of the optical cable, and the end point of the last normal optical cable segment corresponds to the end of the optical cable. The dynamic range of the optical cable can be determined according to the starting point of the first normal optical cable segment and the end point of the last normal optical cable segment. The dynamic range represents the range of normal loss of the optical cable. Therefore, in this embodiment, the difference in signal strength between the starting point of the first normal optical cable segment and the end point of the last normal optical cable segment in the fitted test curve data can be used as the dynamic range of the test optical cable.
[0087] It is understandable that the dynamic range obtained can actually "just" meet the test of the optical cable, but the test results obtained by setting the test parameters in this way may have certain errors, because in the actual test process, once the loss exceeds the dynamic range, there is no way to detect the excess part. Therefore, after obtaining the dynamic range, it is necessary to make a certain correction to the dynamic range. Specifically, the dynamic range can be corrected by adding a preset margin to the dynamic range. The corrected dynamic range can be used as the minimum test pulse width for optical cable testing. Preferably, the preset margin can be set to 5~8dB.
[0088] In this embodiment, the optical cable is measured by using a maximum test pulse width that satisfies the maximum gain of the optical cable. The test curve data obtained by testing with the maximum test pulse width can effectively reflect various information on the optical cable, and can obtain information on various parameters that need to be set for the test at one time, thereby quickly and effectively obtaining parameter information of the optical cable test.
[0089] Example 2
[0090] like Figure 3 As shown, this embodiment provides an optical cable testing system based on OTDR, and the testing system includes:
[0091] A test curve acquisition module 11 is used to measure the optical cable by a maximum test pulse width that satisfies the maximum gain of the optical cable, and obtain corresponding test curve data; the test curve data reflects the length-signal condition of the optical cable;
[0092] In this embodiment, specifically, the optical cable is measured by an optical time domain reflectometer, the optical time domain reflectometer is connected to the optical cable to be tested, and then light with a maximum test pulse width that can meet the maximum gain of the optical cable is emitted from one end of the optical cable, and a corresponding reflection signal is received at the other end to form the test curve data, and the test curve data is displayed by a display device of the optical time domain reflectometer.
[0093] like Figure 2As shown, the test curve data represents the relationship between the measured optical cable length and signal strength, wherein the horizontal axis represents the measured length of the optical cable, and the vertical axis represents the signal strength at the length position of the corresponding optical cable, so the test curve data can reflect the signal conditions of various position points on the optical cable. In this embodiment, light of the maximum test pulse width with maximum gain is injected into the optical cable, and under the action of the light of the maximum test pulse width, the corresponding test curve data is obtained, which effectively reflects the effective test distance of the optical cable and the power attenuation of the optical cable, so that the test parameters of the optical cable can be set conveniently and quickly.
[0094] An event point acquisition module 12 is used to acquire an event start point and an event end point of a signal change event according to the test curve data, and to correct the event start point to obtain a corresponding corrected event start point;
[0095] In this embodiment, if Figure 2 As shown, the test curve data shows an overall downward trend. This is because light will be lost during transmission in the optical cable, resulting in the signal strength of the light gradually decreasing as the length of the optical cable increases.
[0096] Further, from Figure 2 It can also be seen that in the test curve data, the signal strength at several positions suddenly dropped drastically and then stabilized, which means that signal change events occurred at these positions of the optical cable. The signal change events may include reflection events / signal attenuation events, which may be caused by external environmental factors, such as bending of the optical cable, damage to the optical cable, or some conventional factors, such as attenuation at the interface caused by the fusion of the optical cable.
[0097] Therefore, by obtaining the event start point and event end point of the signal change event, it is helpful to identify the signal change event, judge which ones are caused by conventional factors and which ones are caused by external environmental factors, and then realize the maintenance of the optical cable.
[0098] Specifically, in this embodiment, obtaining the event start point and the event end point may specifically include:
[0099] In the test curve data, a curve segment in which the decline of the signal strength exceeds a preset threshold is obtained; the decline refers to the amount of change of the signal strength under a unit distance change. When the decline of the signal strength exceeds the preset threshold, it indicates that the signal strength has dropped drastically, and it can be determined that an event causing signal attenuation loss has occurred here;
[0100] The starting point of the curve segment is used as the event starting point of the signal change event, and the end point of the curve segment is used as the event end point of the signal change event.
[0101] The event starting point obtained by the above method can only include some signal change events. Some signals will suddenly rise before attenuation occurs. When reaching a certain height, there will be a cliff-like drop. Therefore, the event starting point and the corresponding event end point of the signal change event calculated simply by the above method cannot completely cover the entire range of the signal change event. In addition, in the actual measurement process, outside the length range of the optical cable, after the signal strength has dropped to 0, there will still be a part of the signal strength that rises and falls rapidly. This part of the signal strength change is caused by the interference in the optical cable, and this part of the interference needs to be eliminated. At the same time, the signal change events obtained in the test curve data are too dense, and it is not convenient to observe the signal change events. Therefore, it is necessary to calibrate the event starting point. Specifically, the calibration specifically includes:
[0102] In the test curve data, a curve segment with the event starting point as the end point and a continuously rising signal strength is obtained;
[0103] Using the acquired starting point of the curve segment as the starting point of the correction event;
[0104] If the signal strength at the start point of the calibration event is the same as the signal strength at the event end point of the corresponding signal change event, then the signal change event is removed;
[0105] This step is mainly to eliminate interference signal changes outside the length of the optical cable. Because on the optical cable, the signal strength is in a state of continuous attenuation. Even if the signal strength is increased within a certain range after reflection, for the corrected signal change event, the signal strength of the event endpoints before and after the corrected event must be smaller than the signal strength of the correction event endpoint. Therefore, interference can be determined and removed in this way.
[0106] If the distance between the event end point of one signal change event and the correction event starting point of the subsequent signal change event does not exceed the preset distance, the two signal change events are merged into one signal change event, and the correction event starting point of the previous signal change event before the merger is used as the correction event starting point of the merged signal change event, and the event end point of the subsequent signal change event after the merger is used as the end point of the merged signal change event.
[0107] This step is mainly to merge all the signal change events that are too close in distance. In actual scenarios, since the event that affects the signal strength has a range of effects on the optical cable, it usually presents a change in signal strength within a certain length range of the optical cable, that is, if multiple signal change events are too close, it can be said that these signal change events are actually the same signal change event. Therefore, merging the signal change events that are close in distance can integrate the same signal change events, and it can also facilitate the observation of the test curve data.
[0108] The correction event starting point obtained through correction has a larger coverage range than the event starting point before correction, and can include more of the signal change events. At the same time, by adjusting the starting point of the signal change event, some of the signal change events with similar properties can be integrated, thereby facilitating the subsequent calculation of normal optical cable segments and the fitting of the test curve data.
[0109] An optical cable segment acquisition module 13, used for acquiring a normal optical cable segment in the test curve data according to the correction event start point and event end point;
[0110] Specifically, in this embodiment, obtaining the normal optical cable segment may include:
[0111] Taking the curve segment between two consecutive signal change events in the test curve data as the normal optical cable segment, and obtaining a plurality of the normal optical cable segments in the test curve data;
[0112] The normal optical cable section takes the event end point of the first signal change event of the two consecutive signal change events as the starting point, and takes the correction event starting point of the next signal change event as the end point.
[0113] As mentioned above and see Figure 2 The normal optical cable segment represents an area of normal signal strength loss in the test curve data, so the curve segment where normal loss occurs between each signal change event is taken as the normal optical cable segment. Multiple normal optical cable segments can be obtained in the test curve data, and the normal optical cable segment and the signal change event represent the actual length of the optical cable.
[0114] Among them, the starting point of the first normal optical cable segment is the starting point of the optical cable, that is, the port connected to the optical time domain reflectometer. Since it is connected to the optical time domain reflectometer, a reflection event occurs at the starting point; correspondingly, the end point of the last normal optical cable segment is the end of the optical cable.
[0115] An optical cable fitting module 14 is used to fit the test curve data to obtain the optical cable length of the optical cable;
[0116] In this embodiment, the acquisition of the optical cable length of the optical cable can be performed by acquiring the length of the optical cable corresponding to the last event starting point in the fitted test curve data as the optical cable length of the optical cable. The fitting of the test curve data can be performed by fitting the average value of the signal strength of the content within a certain distance range in the test curve data, and a smooth fitted test curve data is obtained by fitting.
[0117] The test curve data after fitting includes all the normal optical cable segments and signal change events, so the coverage of the test curve data after fitting includes the optical cable length of the optical cable. At the end of the optical cable, since the optical cable is connected to the optical cable equipment, signal reflection will occur at the end of the optical cable, that is, a reflection event, and the signal strength will drop to 0. Therefore, the position of the starting point of the last event in the test curve data after fitting is the cable length of the optical cable, which can quickly realize the acquisition of the optical cable length.
[0118] A test distance acquisition module 15, used to acquire the test distance of the optical cable according to the length of the optical cable;
[0119] After obtaining the cable length of the optical cable, it is necessary to further obtain the test distance for the optical cable test. The test distance represents the display range of the test curve data on the display device of the optical time domain reflectometer. In order to be able to display better, in this embodiment, the test distance can be set to 1.5-2 times the cable length of the optical cable. The test curve data set in this way can better and more completely display the relationship between the optical cable length and the signal strength, and when it is necessary to add optical cables in the future, it is convenient to carry out optical cable testing and reposition the test distance of the optical cable.
[0120] The test pulse width acquisition module 16 is used to acquire the minimum test pulse width of the optical cable test according to the normal optical cable segment.
[0121] As described above, the starting point of the first normal optical cable segment corresponds to the front end of the optical cable, and the end point of the last normal optical cable segment corresponds to the end of the optical cable. The dynamic range of the optical cable can be determined according to the starting point of the first normal optical cable segment and the end point of the last normal optical cable segment. The dynamic range represents the range of normal loss of the optical cable. Therefore, in this embodiment, the difference in signal strength between the starting point of the first normal optical cable segment and the end point of the last normal optical cable segment in the fitted test curve data can be used as the dynamic range of the test optical cable.
[0122] It is understandable that the dynamic range obtained can actually "just" meet the test of the optical cable, but the test results obtained by setting the test parameters in this way may have certain errors, because in the actual test process, once the loss exceeds the dynamic range, there is no way to detect the excess part. Therefore, after obtaining the dynamic range, it is necessary to make a certain correction to the dynamic range. Specifically, the dynamic range can be corrected by adding a preset margin to the dynamic range. The corrected dynamic range can be used as the minimum test pulse width for optical cable testing. Preferably, the preset margin can be set to 5~8dB.
[0123] Example 3
[0124] like Figure 4 As shown, this embodiment provides an optical time domain reflectometer, which includes a memory 21 and a processor 22. The memory 21 stores computer-readable instructions, and the processor 22 executes the computer-readable instructions to implement the distributed testing method described in Example 1.
[0125] Preferably, the optical time domain reflectometry device further includes a bus 23 and a communication interface 24 , and the processor 22 , the communication interface 24 and the memory 21 are connected via the bus 23 .
[0126] The memory 21 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk storage. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 24 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used. The bus 23 may be an ISA bus, a PCI bus, or an EISA bus, etc. The bus 23 may be divided into an address bus, a data bus, a control bus, etc. (not fully drawn in the figure).
[0127] The processor 22 may be an integrated circuit chip with signal processing capability. In the specific implementation process, each step in the above method embodiment may be completed by the hardware integrated logic circuit or software instructions in the processor 22. The above processor 22 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, which may implement or execute the methods, steps, and logic diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or the processor 22 may also be any conventional processor 22, etc. The steps of the method disclosed in conjunction with the embodiments of the present invention may be directly embodied as being executed by a hardware decoding processor, or may be executed by a combination of hardware and software modules in a decoding processor. The software module may be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 21, and the processor 22 reads the information in the memory 21 and completes the steps of the method of the above embodiment in combination with its hardware.
[0128] An embodiment of the present invention also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are called and executed by the processor 22, the computer-executable instructions prompt the processor 22 to implement the distributed testing method described above. The specific implementation can be found in the embodiment and will not be repeated here.
[0129] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.
[0130] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.
Claims
1. An optical cable testing method based on OTDR, characterized in that: The test method includes: The optical cable is measured by a maximum test pulse width that satisfies the maximum gain of the optical cable to obtain corresponding test curve data; the test curve data is used to reflect the length-signal condition of the optical cable; Acquire an event start point and an event end point of a signal change event according to the test curve data, and correct the event start point to obtain a corresponding corrected event start point; Acquire the corresponding normal optical cable segment in the test curve data according to the correction event starting point and event end point; Fitting the test curve data to obtain the optical cable length of the optical cable; Acquire a test distance of the optical cable according to the length of the optical cable; Acquire a minimum test pulse width for an optical cable test according to the normal optical cable segment; The correcting the event starting point to obtain a corresponding corrected event starting point specifically includes: In the test curve data, a curve segment with the event starting point as the end point and a continuously rising signal strength is obtained; Using the acquired starting point of the curve segment as the starting point of the correction event; If the distance between the event end point of one signal change event and the correction event starting point of the subsequent signal change event does not exceed the preset distance, the two signal change events are merged into one signal change event, and the correction event starting point of the previous signal change event before the merger is used as the correction event starting point of the merged signal change event, and the event end point of the subsequent signal change event after the merger is used as the end point of the merged signal change event.
2. The optical cable testing method based on OTDR according to claim 1, characterized in that: The step of obtaining the event start point and event end point of the signal change event according to the test curve data specifically includes: In the test curve data, a curve segment whose signal strength decreases by more than a preset threshold is obtained; The starting point of the curve segment is used as the event starting point of the signal change event, and the end point of the curve segment is used as the event end point of the signal change event.
3. The optical cable testing method based on OTDR according to claim 2, characterized in that: After the step of using the acquired starting point of the curve segment as the starting point of the correction event, the method further includes: If the signal intensity at the start point of the calibration event is the same as the signal intensity at the event end point of the corresponding signal change event, the signal change event is removed.
4. The optical cable testing method based on OTDR according to any one of claims 1 to 3, characterized in that: The fitting of the test curve data to obtain the optical cable length of the optical cable specifically includes: Fitting the test curve data; In the fitted test curve data, the length of the optical cable corresponding to the last starting point of the event is obtained as the length of the optical cable.
5. The optical cable testing method based on OTDR according to any one of claims 1 to 3, characterized in that: Acquiring a normal optical cable segment in the test curve data according to the correction event start point and the event end point specifically includes: Taking the curve segment between two consecutive signal change events in the test curve data as the normal optical cable segment, and obtaining a plurality of the normal optical cable segments in the test curve data; The normal optical cable section takes the event end point of the first signal change event of the two consecutive signal change events as the starting point, and takes the correction event starting point of the next signal change event as the end point.
6. The optical cable testing method based on OTDR according to claim 5, characterized in that: The step of obtaining a minimum test pulse width for an optical cable test according to the normal optical cable segment specifically includes: The difference in signal strength between the starting point of the first normal optical cable segment and the end point of the last normal optical cable segment in the fitted test curve data is used as the dynamic range of the optical cable test, and the minimum test pulse width of the optical cable test is obtained according to the dynamic range of the optical cable.
7. The optical cable testing method based on OTDR according to claim 5, characterized in that: The step of obtaining a minimum test pulse width for an optical cable test according to the dynamic range of the optical cable specifically includes: The dynamic range is added with a preset margin to obtain the corrected dynamic range as the minimum test pulse width.
8. An optical cable testing system based on OTDR, characterized in that: The test system comprises: A test curve acquisition module, used to measure the optical cable by a maximum test pulse width that satisfies the maximum gain of the optical cable, and acquire corresponding test curve data; the test curve data is used to reflect the length-signal condition of the optical cable; An event point acquisition module, used for acquiring an event start point and an event end point of a signal change event according to the test curve data, and correcting the event start point to obtain a corresponding corrected event start point; An optical cable segment acquisition module, used for acquiring a normal optical cable segment corresponding to the test curve data according to the correction event start point and event end point; An optical cable fitting module, used for fitting the test curve data to obtain the optical cable length of the optical cable; A test distance acquisition module, used to acquire the test distance of the optical cable according to the length of the optical cable; A test pulse width acquisition module, used to acquire a minimum test pulse width for an optical cable test according to the normal optical cable segment; The correcting the event starting point to obtain a corresponding corrected event starting point specifically includes: In the test curve data, a curve segment with the event starting point as the end point and a continuously rising signal strength is obtained; Using the acquired starting point of the curve segment as the starting point of the correction event; If the distance between the event end point of one signal change event and the correction event starting point of the subsequent signal change event does not exceed the preset distance, the two signal change events are merged into one signal change event, and the correction event starting point of the previous signal change event before the merger is used as the correction event starting point of the merged signal change event, and the event end point of the subsequent signal change event after the merger is used as the end point of the merged signal change event.
9. An optical time domain reflectometer device, comprising a memory and a processor, characterized in that: The memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the OTDR-based optical cable testing method according to any one of claims 1 to 7.
10. A computer storage medium, characterized in that: A computer-readable program is stored thereon, and when the computer-readable program is executed, the optical cable testing method based on OTDR described in any one of claims 1 to 7 is implemented.