WO2007112631A1 - Procédé et dispositif pour tester le niveau d'équilibre longitudinal d'une ligne - Google Patents

Procédé et dispositif pour tester le niveau d'équilibre longitudinal d'une ligne Download PDF

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Publication number
WO2007112631A1
WO2007112631A1 PCT/CN2007/000197 CN2007000197W WO2007112631A1 WO 2007112631 A1 WO2007112631 A1 WO 2007112631A1 CN 2007000197 W CN2007000197 W CN 2007000197W WO 2007112631 A1 WO2007112631 A1 WO 2007112631A1
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WO
WIPO (PCT)
Prior art keywords
line
frequency
frequency point
amplitude
tested
Prior art date
Application number
PCT/CN2007/000197
Other languages
English (en)
Chinese (zh)
Inventor
Hongya Wang
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to CN2007800004142A priority Critical patent/CN101322324B/zh
Publication of WO2007112631A1 publication Critical patent/WO2007112631A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/46—Monitoring; Testing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/30—Reducing interference caused by unbalanced currents in a normally balanced line

Definitions

  • the present invention relates to the field of telecommunications networks, and more particularly to a method and apparatus for testing the longitudinal balance of a line. Background technique
  • ADSL over POTS ADSL over PODSL
  • ADSL over ISDN ISDN ESD
  • VDSL over POTS VDSL over PODSL
  • VDSL over ISDN ISDN extended VDSL
  • other services such applications have been quite common in China and abroad.
  • ADSL and VDSL are collectively referred to as xDSL
  • the xDSL signal and the POTS/ISDN signal coexist in one user's external line.
  • the splitter (SPL) in the interoffice broadband equipment (DSLAM) separates the wide and narrow services and sends them separately.
  • the broadband service board (xDSL service board) and the narrowband service board (POTS/ISDN service board) are processed, and on the user side, the splitter in the interoffice broadband equipment sends the separated wide and narrowband services to the client. RTU and phone.
  • the longitudinal balance is used to measure the longitudinal balance performance of the line, that is, the line-to-ground imbalance performance.
  • the longitudinal balance of the line is an important indicator to measure the quality of the line when the line is used for high-speed data transmission. This is mainly because: the line-to-ground imbalance may cause a potential difference between the two lines of the pair, and then form between the two lines.
  • the potential loop creates a loop current that causes additional interference. Due to the existence of the potential loop, an electromagnetic field is formed around the line, causing a large amount of external interference to be integrated into the line, affecting normal communication.
  • the national standard provides for the opening of ADSL. Service requirements: For the ADSL service, the longitudinal conversion loss is not less than 50 dB in the range of 26 kHz to 1104 kHz, and is allowed to be greater than 40 dB in special cases.
  • the longitudinal balance Bm-1 is defined as:
  • the Em in the above formula is called the lateral voltage, as shown in Figure 2, that is, the potential difference between the line TIP and the RING line terminal, also called the differential mode amplitude.
  • E1 is called vertical voltage, which is caused by the imbalance of TIP and RING lines to ground.
  • E1 is equal to 1/2 of the left-to-ground potential difference of R1 and the sum of the left-to-ground potential difference of R2, also called common mode amplitude.
  • the line test may actually be much larger than the differential mode amplitude due to line imbalance.
  • V the differential mode amplitude caused by non-line imbalance factors (such as noise)
  • A 201og(" " ⁇ .
  • the influence of the longitudinal sheep's balance is floating up and down within a fixed interval.
  • the hardware design currently used is to send a common mode signal and measure the differential mode signal.
  • the digital signal processing module DSP generates a modulation signal to D/A, and the D/A device is converted into a common mode analog signal and then sent to the actual differential line. Due to the existence of the line imbalance factor, the differential line actually The voltages are not equal, there is a potential difference, the differential signal is converted into a standard differential signal by a differential transformer, and then the sampled data is processed by the A/D device, and the DSP performs processing on the received sampled data by FFT (Fast Fourier Transform). The frequency domain differential amplitude of each corresponding frequency point is calculated, thereby realizing the calculation of the longitudinal balance degree.
  • FFT Fast Fourier Transform
  • the current test line There are two options for the vertical balance of the road.
  • step X15 judging whether all frequency points are sent, if not, return to step XII; if the sending is finished, proceed to step X16;
  • the energy of the frequency point to be measured can be set relatively large, has a high signal to noise ratio, and has strong anti-noise ability, so that the longitudinal balance of the test can be accurately reflected.
  • the actual balance of the line See the above formula for calculating the vertical balance of the actual line.
  • This scheme can make the common mode amplitude! ⁇ large enough, the differential mode amplitude is similar to the differential mode amplitude caused by the line imbalance, that is, the influence on the line balance Small.
  • the entire processing time is too long, and the "sensitivity" requirement of the test for time cannot be well satisfied.
  • the scheme has the advantage of fast calculation speed, but considering the actual bearing capacity of the hardware circuit, the sum of the energy of the modulated combined wave cannot exceed the actual bearing capacity of the hardware circuit, and the energy of each transmitting frequency needs to be reduced by multiple times, due to the influence of test line noise and the like.
  • the existence of vertical balance factors The signal-to-noise ratio is relatively small, and the noise resistance of each frequency point signal is poor, which causes noise and the like to have a large influence on the longitudinal balance degree, so that the test result cannot truly reflect the actual balance of the line. See the above formula for calculating the vertical balance of the actual line.
  • This scheme can make the common mode amplitude small enough. In the case of ideal line balance, the differential mode amplitude is approximately 1 awake, that is, legislativepair balance most influential. Summary of the invention
  • the embodiment of the invention provides a method and a device for testing the longitudinal balance of a line, which are used to solve the problem of long test time in the prior art, and solve the problem that the non-line imbalance factor in the prior art 2 has a great influence on the test result. problem.
  • the method of the present invention includes: determining a reliable common mode amplitude of each frequency point to be tested; grouping each frequency point according to the measured line characteristic and the reliable common mode amplitude; and calculating each of the groups in units of The vertical balance of each frequency point in the group.
  • the device for testing the longitudinal balance of the line includes: a frequency generating module, configured to combine the frequency points to be transmitted to generate a modulated signal of the excitation signal source, and send the modulated signal to the line to be tested; and a longitudinal balance calculation module, configured to The modulated signal on the measured line calculates the longitudinal balance of each frequency point; the reliable amplitude determining module is used to determine the reliable common mode amplitude of each frequency point; the grouping module is used to determine the characteristics and reliability of the measured line The reliable common mode amplitude outputted by the amplitude determining module groups each frequency point and outputs it to the frequency generating module one by one in units of groups.
  • the embodiment of the method of the present invention no longer directly sends the common mode amplitude of the single frequency point to the differential line for testing, and does not generate the modulated wave common mode signal for all the frequency points to be measured, and sends the modulated signal to the line. Test on it.
  • the method embodiment of the present invention considers the noise interference of the actual line, and obtains the reliable common mode amplitude of each frequency point to be tested according to the noise difference mode amplitude of each frequency to be measured, and further according to the characteristics of the tested line and the described The reliable common mode amplitude groups each frequency point. Finally, the vertical balance of each frequency point in each group is calculated in units of groups.
  • the method of the invention emits more than one frequency to be tested at a time, reducing The number of transmissions is saved, thereby saving test time; and according to the above grouping strategy, the effect of the prior art that accurately reflects the actual balance of the line is also inherited.
  • the method of the invention emits several but not all frequency points to be tested at a time.
  • the energy of each frequency point is increased, but the line load can be satisfied, so that the effect of accurately reflecting the actual balance condition of the line can be achieved; and since the grouping strategy is adopted, the prior art second test is also inherited. Faster speed effect.
  • Embodiments of the present invention also provide an apparatus for testing the longitudinal balance of a line.
  • Figure 1 is a schematic diagram of an existing xDSL service
  • FIG. 2 is a circuit schematic diagram of a conventional differential mode amplitude and a common mode amplitude
  • FIG. 3 is a schematic diagram of a hardware structure of an existing test longitudinal balance
  • FIG. 5 is a flow chart showing the steps of all existing transmission methods of frequency points to be tested.
  • FIG. 6 is a schematic diagram of a hardware structure for testing a longitudinal flat copper-degree according to an embodiment of the present invention.
  • FIG. 7 is a flow chart showing the steps of an embodiment of the method of the present invention. detailed description
  • the embodiment of the invention provides a device for testing the longitudinal balance of the line, which is applied to the ADSL line and can also be applied to other xDSL lines.
  • the method includes: a reliable amplitude determining module, a grouping module, a frequency generating module, and a longitudinal balance calculating module connected in sequence.
  • the reliable amplitude determining module is configured to calculate a noise difference mode amplitude of each frequency point in the tested line, and determine a reliable common mode amplitude of each frequency point.
  • the grouping module is configured to group each frequency point according to the measured common line amplitude of the measured line characteristic and the reliable amplitude determining module output, and output to the frequency generating mode one by one in units of groups
  • the frequency generating module is configured to combine the frequency points to be transmitted to generate a modulated signal of the excitation signal source, and send the modulated signal to the line to be tested.
  • the longitudinal balance calculation module is configured to calculate a longitudinal balance degree of each corresponding frequency point according to a modulation signal on the measured line.
  • the above-described frequency generation module and longitudinal balance calculation module have the same functions as the existing vertical balance test device shown in Fig. 3.
  • An embodiment of the present invention provides a method for testing the longitudinal balance of a line. Referring to FIG. 7, the method example includes the following specific steps:
  • the results of the longitudinal balance test are scheduled to be: When the noise power spectral density is relatively large (such as -lOOdbm or -90dbm), the longitudinal balance of the line after the noise influence is more than 60db. Take the noise power spectral density as -90dbm as an example.
  • the frequency range to be sought is 0 to 2.2 MHz, and other lines are subject to the relevant protocol.
  • the noise power spectral density PSD of the random noise signal in the ADSL signal unit Tone unit bandwidth is:
  • N is the FFT calculation point
  • 2 is the characteristic impedance corresponding to the frequency point on the transmission line
  • SPf is the width of the tone
  • . is the sampling frequency.
  • the " 2 " in the above formula is defined as: , int means rounding down.
  • Set: FFT points N 16K, 100 ohms, measured noise power spectral density maximum -90dbm (given in step SI).
  • the amplitudes of other frequency points are calculated separately.
  • step S3 Assume that the maximum voltage amplitude of the signal on the line at the same time determined by the hardware performance of the board cannot exceed 3V, and the reliable common mode amplitude obtained according to step S3 is 300MV.
  • the maximum number of transmission frequency points at the same time is 3V/300MV-10, that is, in this embodiment, the maximum number of transmission frequency points per group is 10.
  • the number of frequency points per transmission is set to 10 (or may not be evenly grouped). 7
  • the number of frequency points to be measured is 512-6+1, combined with the set frequency of 10 frequency points.
  • the amplitude of the frequency to be measured is 300 MV, and each group sends 10 frequency points, which are sent a total of 51 times.
  • the number of transmissions is reduced from 507 to 51 times, which obviously saves the test time;
  • the transmission amplitude of the frequency to be tested is increased to 300 MV, which can meet the test requirements.
  • the respective frequency points in the group to be tested are combined to generate a modulation signal of the excitation signal source, and sent to the test line.
  • the DSP samples the time domain information on the line, and calculates the frequency domain differential amplitude corresponding to each frequency point in the group by FFT or the like, and records it as J .
  • the longitudinal balance of each frequency point in the group can be calculated as:

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Monitoring And Testing Of Exchanges (AREA)

Abstract

L'invention concerne un procédé et un dispositif servant à tester le niveau d'équilibre longitudinal d'une ligne, en vue de résoudre le problème de la durée du temps d'essai rencontré dans la première technique antérieure, et le problème du facteur de déséquilibre hors ligne ayant une grande influence sur le résultat de l'essai dans la seconde technique antérieure. Le procédé consiste à: déterminer une amplitude de mode commun fiable de chaque point de fréquence à tester; placer chaque point de fréquence dans un groupe en fonction des caractéristiques de la ligne à tester et de ladite amplitude de mode commun fiable; et calculer respectivement le niveau d'équilibre longitudinal de la ligne pour chaque point de fréquence de chaque groupe, ce qui, selon l'invention, réduit le temps d'essai et reflète précisément et véritablement l'état déquilibre réel de la ligne.
PCT/CN2007/000197 2006-04-05 2007-01-18 Procédé et dispositif pour tester le niveau d'équilibre longitudinal d'une ligne WO2007112631A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2007800004142A CN101322324B (zh) 2006-04-05 2007-01-18 一种测试线路纵向平衡度的方法及装置

Applications Claiming Priority (2)

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CNB2006100671919A CN100454939C (zh) 2006-04-05 2006-04-05 一种测试线路纵向平衡度的方法及装置
CN200610067191.9 2006-04-05

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2550752A4 (fr) * 2010-03-26 2017-08-23 Telefonaktiebolaget LM Ericsson (publ) Estimation de l'état de symétrie d'une paire pour une ligne de transmission
CN114355086A (zh) * 2022-01-05 2022-04-15 北京航空航天大学 一种基于分组测试的天线端口互调传导敏感度测量方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1148305A (zh) * 1995-08-18 1997-04-23 三星电子株式会社 在转发线中的馈电不平衡检测
US6167259A (en) * 1998-06-19 2000-12-26 Ericsson Inc. System and method of quantifying the degree of balance on forward link and reverse link channels
CN1434596A (zh) * 2002-01-24 2003-08-06 深圳市中兴通讯股份有限公司 Cdma基站接收链路检测的方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100456839C (zh) * 2003-07-12 2009-01-28 华为技术有限公司 一种数字用户线路的测试系统及测试方法
CN1588966A (zh) * 2004-09-27 2005-03-02 新太科技股份有限公司 Adsl线路参数的测试方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1148305A (zh) * 1995-08-18 1997-04-23 三星电子株式会社 在转发线中的馈电不平衡检测
US6167259A (en) * 1998-06-19 2000-12-26 Ericsson Inc. System and method of quantifying the degree of balance on forward link and reverse link channels
CN1434596A (zh) * 2002-01-24 2003-08-06 深圳市中兴通讯股份有限公司 Cdma基站接收链路检测的方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2550752A4 (fr) * 2010-03-26 2017-08-23 Telefonaktiebolaget LM Ericsson (publ) Estimation de l'état de symétrie d'une paire pour une ligne de transmission
CN114355086A (zh) * 2022-01-05 2022-04-15 北京航空航天大学 一种基于分组测试的天线端口互调传导敏感度测量方法
CN114355086B (zh) * 2022-01-05 2024-06-07 北京航空航天大学 一种基于分组测试的天线端口互调传导敏感度测量方法

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CN100454939C (zh) 2009-01-21
CN101322324B (zh) 2012-08-29
CN101322324A (zh) 2008-12-10
CN1968309A (zh) 2007-05-23

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