CN102426363B - A Method of Improving Event Distance Accuracy Based on Phase Shift Technology in OTDR Design - Google Patents
A Method of Improving Event Distance Accuracy Based on Phase Shift Technology in OTDR Design Download PDFInfo
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- CN102426363B CN102426363B CN 201110255059 CN201110255059A CN102426363B CN 102426363 B CN102426363 B CN 102426363B CN 201110255059 CN201110255059 CN 201110255059 CN 201110255059 A CN201110255059 A CN 201110255059A CN 102426363 B CN102426363 B CN 102426363B
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Abstract
The invention discloses a method for improving event distance accuracy based on phase shift technology in OTDR (Optical Time Domain Reflectometry) design, in particular to a method for improving event distance accuracy by virtue of a set clock phase shifting device under the condition that A/D (Analog-to-Digital) sampling frequency is definite. The device comprises a clock phase shifting module, an optical pulse generating module, an optical pulse selecting module and a storage control module, wherein the clock phase shifting module is respectively connected with an original clock and the optical pulse generating module, the optical pulse generating module is connected with the optical pulse selecting module, and the optical pulse selecting module is connected with the storage control module. The method disclosed by the invention can effectively improve the event distance accuracy under the condition that the A/D sampling frequency is constant and also has the characteristics of less equipment, low cost, low circuit design difficulty.
Description
Technical field
The present invention relates to the test optical fiber field, in particular, is a kind of method and device that improves the incident distance precision in the OTDR design based on phase shift technology.
Background technology
Along with optical fiber communication use more and more extensive, to improving constantly of the requirement of the test job of optical fiber.The incident distance test is as an importance of test job, and the requirement of its precision also improves constantly.In the OTDR test, the precision of incident distance depends on the frequency of A/D sampling.OTDR test be by the utilizing emitted light pulse in testing fiber, when light pulse is transmitted, can produce scattering, reflection owing to character, connector, bending or other similar event of optical fiber itself in optical fiber.Wherein scattering and the reflection of a part turn back among the OTDR, and be accurately corresponding with the time the luminous energy that turns back among the OTDR, connects into the OTDR curve that a curve just obtains testing fiber.Wherein the distance of event is by formula:
d=(c×t)/2(IOR)
In this formula, c is light speed in a vacuum, and t is to the T.T. that receives signal (round trip) (it is exactly the distance of one way that two values multiply each other after 2) after the signal emission.Because light is slower than speed in a vacuum in glass, so for measuring distance accurately, tested optical fiber must indicate refractive index (IOR).IOR is indicated by the optical fiber production merchant.Wherein time t is the integral multiple in A/D sampling period.Therefore the precision that improves incident distance just must shorten the A/D sampling period, namely improves the sample frequency of A/D.But the A/D sample frequency is to improve, and also brings the raising of PCB fabric swatch requirement simultaneously, has increased the circuit design difficulty, has also improved equipment cost.
Summary of the invention
The objective of the invention is for overcoming the deficiencies in the prior art, and a kind of method and device that improves the incident distance precision in OTDR design based on phase shift technology be provided, it is low that the method has the equipment cost of minimizing, reduces the circuit design difficulty, improves the characteristics such as incident distance precision.
The technical scheme that realizes the object of the invention is:
A kind of method that improves the incident distance precision in the OTDR design based on phase shift technology is a kind of in the certain situation of A/D sample frequency, and by the method for clock phase shift technology raising incident distance precision, the method comprises the steps:
(1) set up a clock phase shifting equipment in the OTDR design and be connected with original clock, this device comprises clock phase shift block, optical pulse generation module, light pulse selection module and storage control module;
(2) testing fiber is input in the clock phase shift block through original clock;
(3) the clock phase shift block produces respectively two clocks of 0 phase place and 180 phase places according to two phase phase shift, four phase place phase shifts or eight-phase phase shift, or produce four clocks of 0 phase place, 90 phase places, 180 phase places and 270 phase places, or produce the phase differential of eight clocks of 0 phase place, 45 phase places, 90 phase places, 135 phase places, 180 phase places, 225 phase places, 270 phase places and 315 phase places, output to corresponding optical pulse generation module;
(4) the optical pulse generation module produces the poor light pulse signal of corresponding time delay phase and selects module to light pulse;
(5) after the light pulse poor light pulse signal of time delay phase of selecting module that the light pulse module is produced carries out alternate selection, output to storage control module;
(6) storage control module selects the light pulse signal of the time delay of module output to store control according to light pulse, and the spacing distance of the sampled point in the storer in the link address just is equivalent to the incident distance precision.
Be used for being implemented in the OTDR design and comprise the clock phase shifting equipment based on the device that phase shift technology improves the incident distance precision methods, this device comprises clock phase shift block, optical pulse generation module, light pulse selection module and storage control module, the original clock input is connected with the clock phase shift block, the clock phase shift block is connected with the optical pulse generation module, the optical pulse generation module selects module to be connected with light pulse, and light pulse selects module to be connected with memory control module.
During described clock phase shift block two phase output, the optical pulse generation module is two; During the output of four phase places, the optical pulse generation module is four; During eight-phase output, the optical pulse generation module is eight.
Described clock phase shift block two phase is output as 0 phase place and 180 phase places;
Four phase places are output as 0 phase place, 90 phase places, 180 phase places, 270 phase places;
Eight-phase is output as 0 phase place, 45 phase places, 90 phase places, 135 phase places, 180 phase places, 225 phase places, 270 phase places, the output of 315 phase places.
Advantage of the present invention is: in the constant situation of A/D sample frequency, and precision that can not only the Effective Raise incident distance; Also have minimizing equipment, cost is low, reduces the characteristics such as circuit design difficulty.
Description of drawings
Fig. 1 is the embodiment of the invention 1 two phase phase-shift structure synoptic diagram;
Fig. 2 is the embodiment of the invention 2 four phase shift phase structure synoptic diagram;
Fig. 3 is the embodiment of the invention 3 eight-phase phase-shift structure synoptic diagram.
Embodiment
The invention will be further elaborated below in conjunction with drawings and Examples.
Embodiment 1: the two phase phase shift
With reference to Fig. 1, the clock phase shifting equipment of present embodiment comprises 5 parts, is respectively that module 3 and storage control module 4 are selected in clock phase shift block 1, the first optical pulse generation module 2-1, the second optical pulse generation module 2-2, the light pulse that is linked in sequence.The course of work is as follows: suppose that the A/D sampling period is T, clock phase shift block 1 produces two clocks of 0 phase place and 180 phase places, and then the phase differential of two clocks is T/2; The first optical pulse generation module 2-1 and the second optical pulse generation module 2-2 produce the light pulse signal that two kinds of time delays differ T/2; Light pulse selects two time delays of module 3 alternate selection to differ the light pulse signal of T/2, the light pulse signal of test selection 0 phase place for the first time, the light pulse signal of test selection 180 phase places for the second time, the light pulse signal of test selection 0 phase place for the third time, the light pulse signal of the 4th test selection 180 phase places, the like this light pulse signal of two kinds of time delays of alternate selection output; Storage control module 4 selects the light pulse signal of module 3 which kind of time delay of output to store control according to light pulse, if light pulse signal is 0 phase place, then be stored in the memory address space of the odd number such as the 1st, the 3rd, the 5th, if light pulse signal is 180 phase places, then be stored in the memory address space of the even number such as the 2nd, the 4th, the 6th, the interval of the sampled point in the link address is exactly T/2 in the storer like this, it is T/2 that the incident distance precision just is equivalent to the A/D sampling period, and namely the incident distance precision is brought up to original 2 times.
Embodiment 2 four phase place phase shifts
With reference to Fig. 2, the clock phase shifting equipment of present embodiment comprises 7 parts, is respectively that module 3 and storage control module 4 are selected in clock phase shift block 1, the first optical pulse generation module 2-1, the second optical pulse generation module 2-2, the 3rd optical pulse generation module 2-3, the 4th optical pulse generation module 2-4, the light pulse that is linked in sequence.The course of work is as follows: suppose that the A/D sampling period is T, clock phase shift block 1 produces four clocks of 0 phase place, 90 phase places, 180 phase places and 270 phase places, and the phase differential of two clocks that then continue is T/4; The first optical pulse generation module 2-1, the second optical pulse generation module 2-2, the 3rd optical pulse generation module 2-3, the 4th optical pulse generation module 2-4 produce the light pulse signal that 4 kinds of time delays differ T/4; Light pulse selects four time delays of module 3 alternate selection to differ the light pulse signal of T/4, the light pulse signal of test selection 0 phase place for the first time, the light pulse signal of test selection 90 phase places for the second time, the light pulse signal of test selection 180 phase places for the third time, the light pulse signal of the 4th test selection 270 phase places, the like this light pulse signal of four kinds of time delays of alternate selection output; Storage control module 4 selects the light pulse signal of module 3 which kind of time delay of output to store control according to light pulse, if light pulse signal is 0 phase place, then be stored in the 1st, the 5th, the 9th grade is in 1 the memory address space to 4 deliverys, if light pulse signal is 90 phase places, then be stored in the 2nd, the 6th, the 10th grade is in 2 the memory address space to 4 deliverys, if light pulse signal is 180 phase places, then be stored in the 3rd, the 7th, the 11st grade is in 3 the memory address space to 4 deliverys, if light pulse signal is 270 phase places, then be stored in the 4th, the 8th, the 12nd grade is in 0 the memory address space to 4 deliverys, the interval of the sampled point in the link address is exactly T/4 in the storer like this, it is T/4 that the incident distance precision just is equivalent to the A/D sampling period, and namely the incident distance precision is brought up to original 4 times.
Embodiment 3 eight-phase phase shifts
With reference to Fig. 3, the clock phase shifting equipment of present embodiment comprises 11 parts, is respectively that module 3 and storage control module 4 are selected in clock phase shift block 1, the first optical pulse generation module 3-1, the second optical pulse generation module 3-2, the 3rd optical pulse generation module 3-3, the 4th optical pulse generation module 3-4, the 5th optical pulse generation module 3-5, the 6th optical pulse generation module 3-6, the 7th optical pulse generation module 3-7, the 8th optical pulse generation module 3-8, the light pulse that is linked in sequence.The course of work is as follows: suppose that the A/D sampling period is T, clock phase shift block 1 produces 8 clocks of 0 phase place, 45 phase places, 90 phase places, 135 phase places, 180 phase places, 225 phase places, 270 phase places and 315 phase places, and the phase differential of two clocks that then continue is T/8; The first optical pulse generation module 3-1, the second optical pulse generation module 3-2, the 3rd optical pulse generation module 3-3, the 4th optical pulse generation module 3-4, the 5th optical pulse generation module 3-5, the 6th optical pulse generation module 3-6, the 7th optical pulse generation module 3-7, the 8th optical pulse generation module 3-8 produce the light pulse signal that 8 kinds of time delays differ T/8; Light pulse selects 8 time delays of module 3 alternate selection to differ the light pulse signal of T/4, the light pulse signal of test selection 0 phase place for the first time, the for the second time light pulse of test selection 45 phase places, the light pulse signal of test selection 90 phase places for the third time, the light pulse signal of the 4th test selection 135 phase places, the light pulse signal of the 5th test selection 180 phase places, the light pulse signal of the 6th test selection 225 phase places, the light pulse signal of the 7th test selection 270 phase places, the light pulse signal of the 8th test selection 315 phase places, the like this light pulse signal of 8 kinds of time delays of alternate selection output; Storage control module 4 selects the light pulse signal of module 3 which kind of time delay of output to store control according to light pulse signal, if light pulse signal is 0 phase place, then be stored in the 1st, the 9th, the 17th grade is in 1 the memory address space to 8 deliverys, if light pulse signal is 45 phase places, then be stored in the 2nd, the 10th, the 18th grade is in 2 the memory address space to 8 deliverys, if light pulse signal is 90 phase places, then be stored in the 3rd, the 11st, the 19th grade is in 3 the memory address space to 8 deliverys, if light pulse signal is 135 phase places, then be stored in the 4th, the 12nd, the 20th grade is in 4 the memory address space to 8 deliverys, if light pulse signal is 180 phase places, then be stored in the 5th, the 13rd, the 21st grade is in 5 the memory address space to 8 deliverys, if light pulse signal is 225 phase places, then be stored in the 6th, the 14th, the 22nd grade is in 6 the memory address space to 8 deliverys, if light pulse signal is 270 phase places, then be stored in the 7th, the 15th, the 23rd grade is in 7 the memory address space to 8 deliverys, if light pulse signal is 315 phase places, then be stored in the 8th, the 16th, the 24th grade is in 0 the memory address space to 8 deliverys, the interval of the sampled point in the link address is exactly T/8 in the storer like this, it is T/8 that the incident distance precision just is equivalent to the A/D sampling period, and namely A incident distance precision is brought up to original 8 times.
Claims (4)
1. a method that improves the incident distance precision in the OTDR design based on phase shift technology is a kind of in the certain situation of A/D sample frequency, and by the method for clock phase shift technology raising incident distance precision, the method comprises the steps:
(1) set up a clock phase shifting equipment in the OTDR design and be connected with original clock, the clock phase shifting equipment comprises clock phase shift block, optical pulse generation module, light pulse selection module and storage control module;
(2) testing fiber is input in the clock phase shift block through original clock;
(3) the clock phase shift block produces respectively two clocks of 0 phase place and 180 phase places according to two phase phase shift, four phase place phase shifts or eight-phase phase shift, or produce four clocks of 0 phase place, 90 phase places, 180 phase places and 270 phase places, or produce the phase differential of eight clocks of 0 phase place, 45 phase places, 90 phase places, 135 phase places, 180 phase places, 225 phase places, 270 phase places and 315 phase places, output to corresponding optical pulse generation module;
(4) the optical pulse generation module produces the poor light pulse signal of corresponding time delay phase and selects module to light pulse;
(5) after the light pulse poor light pulse signal of time delay phase of selecting module that the optical pulse generation module is produced carries out alternate selection, output to storage control module;
(6) storage control module selects the light pulse signal of the time delay of module output to store control according to light pulse, and the spacing distance of the sampled point in the storer in the link address just is equivalent to the incident distance precision.
2. be used for realizing the device of the described method of claim 1, it is characterized in that: the clock phase shift block in this device is connected with original clock, optical pulse generation module respectively, the optical pulse generation module selects module to be connected with light pulse, and light pulse selects module to be connected with memory control module; The clock phase shift block produces respectively two clocks of 0 phase place and 180 phase places according to two phase phase shift, four phase place phase shifts or eight-phase phase shift, or produce four clocks of 0 phase place, 90 phase places, 180 phase places and 270 phase places, or produce the phase differential of eight clocks of 0 phase place, 45 phase places, 90 phase places, 135 phase places, 180 phase places, 225 phase places, 270 phase places and 315 phase places, output to corresponding optical pulse generation module; The optical pulse generation module produces the poor light pulse signal of corresponding time delay phase and selects module to light pulse; After the poor light pulse signal of time delay phase that light pulse selects module that the optical pulse generation module is produced carries out alternate selection, output to storage control module; Storage control module selects the light pulse signal of the time delay of module output to store control according to light pulse, and the spacing distance of the sampled point in the storer in the link address just is equivalent to the incident distance precision.
3. device according to claim 2 is characterized in that: during described clock phase shift block two phase output, the optical pulse generation module is two; During the output of four phase places, the optical pulse generation module is four; During eight-phase output, the optical pulse generation module is eight.
4. device according to claim 2, it is characterized in that: described clock phase shift block two phase is output as 0 phase place and 180 phase places; Four phase places are output as 0 phase place, 90 phase places, 180 phase places, 270 phase places; Eight-phase is output as 0 phase place, 45 phase places, 90 phase places, 135 phase places, 180 phase places, 225 phase places, 270 phase places, the output of 315 phase places.
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| JP6989073B2 (en) * | 2016-03-25 | 2022-01-05 | マーベル ワールド トレード リミテッド | Systems and methods for precision cable length measurement in communication systems |
| CN111555801A (en) * | 2020-04-28 | 2020-08-18 | 昂纳信息技术（深圳）有限公司 | Optical signal sampling device and method for optical time domain reflectometer and optical time domain reflectometer |
| CN113783607B (en) * | 2021-08-30 | 2023-04-14 | 昂纳科技(深圳)集团股份有限公司 | A dual-clock out-of-phase sampling device, its sampling method, and an optical time domain reflectometer |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2165118A (en) * | 1984-09-29 | 1986-04-03 | Plessey Co Plc | OTDR for sensing distortions in optical fibres |
| CN2816781Y (en) * | 2005-07-21 | 2006-09-13 | 北京信诺光维科技发展有限公司 | OTDR |
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- 2011-08-31 CN CN 201110255059 patent/CN102426363B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2165118A (en) * | 1984-09-29 | 1986-04-03 | Plessey Co Plc | OTDR for sensing distortions in optical fibres |
| CN2816781Y (en) * | 2005-07-21 | 2006-09-13 | 北京信诺光维科技发展有限公司 | OTDR |
Non-Patent Citations (4)
| Title |
|---|
| OTDR在光纤测量中的应用;马正先等;《激光杂志》;19990228;第20卷(第2期);1-7 * |
| 传输高稳定原子钟信号的光纤模拟通信系统;李立汉等;《电子设计工程》;20090831;第17卷(第8期);28-30 * |
| 李立汉等.传输高稳定原子钟信号的光纤模拟通信系统.《电子设计工程》.2009,第17卷(第8期),28-30. |
| 马正先等.OTDR在光纤测量中的应用.《激光杂志》.1999,第20卷(第2期),1-7. |
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Inventor after: Xiao Danyi Inventor after: Liu Fuqi Inventor after: Huang Fengling Inventor after: Zhou Xiaowei Inventor after: Li Lihan Inventor after: Ni Mingfang Inventor before: Xiao Danyi Inventor before: Liu Fuqi Inventor before: Huang Fengling Inventor before: Zhou Xiaowei Inventor before: Li Lihan |
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Effective date of registration: 20150730 Address after: 541004 the Guangxi Zhuang Autonomous Region Guilin, Liuhe Road, No. 98 Patentee after: Guilin G-Link Technology Co., Ltd. Patentee after: Univ. of Science and Engineering, PLA Address before: 541004 the Guangxi Zhuang Autonomous Region Guilin, Liuhe Road, No. 98 Patentee before: Guilin G-Link Technology Co., Ltd. |