Printed by Jouve, 75001 PARIS (FR) (19) EP 2 1 12 810 A1 & (11) EP 2 1 12 810 A1 (12) EUROPEAN PATENT APPLICATION published in accordance with Art. 153(4) EPC (43) Date of publication: 28.10.2009 Bulletin 2009/44 (21) Application number: 08854824.3 (22) Date of filing: 07.11.2008 (51) Int Cl.: H04M 3/30 (2006.01) H04B 3/46 (2006.01) (86) International application number: PCT/CN2008/072974 (87) International publication number: WO 2009/067898 (04.06.2009 Gazette 2009/23) (84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR (30) Priority: 09.11.2007 CN 200710188123 (71) Applicant: Huawei Technologies Co., Ltd. Longgang District Shenzhen Guangdong 518129 (CN) (72) Inventor: ZHANG, Pengrui Guangdong 518129 (CN) (74) Representative: Kreuz, Georg Maria Huawei Technologies Riesstrasse 25 80992 München (DE) (54) LINE MEASURING METHOD AND DEVICE (57) A line measurement method includes: obtaining data of relation between a line length and an insertion loss phase radian, and obtaining data of relation between the line length and a loop attenuation parameter value; obtaining four length values from the data of relation be- tween the line length and the insertion loss phase radian, and defining a length range to obtain the first and the second length range; and determining the boundary of the second length range close to a midpoint of the first length range, using a line length value corresponding to the boundary close to the midpoint as a measured line length, and using a line diameter corresponding to the line length value as a measured line diameter.
Transcript
Printed by Jouve, 75001 PARIS (FR)
(19)E
P2
112
810
A1
& (11) EP 2 112 810 A1
(12) EUROPEAN PATENT APPLICATIONpublished in accordance with Art. 153(4) EPC
(43) Date of publication: 28.10.2009 Bulletin 2009/44
(21) Application number: 08854824.3
(22) Date of filing: 07.11.2008
(51) Int Cl.:H04M 3/30 (2006.01) H04B 3/46 (2006.01)
(86) International application number: PCT/CN2008/072974
(87) International publication number: WO 2009/067898 (04.06.2009 Gazette 2009/23)
(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
(74) Representative: Kreuz, Georg MariaHuawei Technologies Riesstrasse 2580992 München (DE)
(54) LINE MEASURING METHOD AND DEVICE
(57) A line measurement method includes: obtainingdata of relation between a line length and an insertionloss phase radian, and obtaining data of relation betweenthe line length and a loop attenuation parameter value;obtaining four length values from the data of relation be-tween the line length and the insertion loss phase radian,and defining a length range to obtain the first and thesecond length range; and determining the boundary ofthe second length range close to a midpoint of the firstlength range, using a line length value corresponding tothe boundary close to the midpoint as a measured linelength, and using a line diameter corresponding to theline length value as a measured line diameter.
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Description
[0001] This application claims priority to Chinese patent application No. 200710188123.2, filed with the Chinese PatentOffice on November 9, 2007 and entitled "Line Measurement Method and Measurement Apparatus", which is incorporatedherein by reference in its entirety.
Field of the Invention
[0002] The present invention relates to line measurement technologies, and in particular, to a line measurementmethod and a measurement apparatus.
Background of the Invention
[0003] With the expansion of the Digital Subscriber Line Access Multiplexer (DSLAM) network, it is necessary to selectsubscriber lines quickly, to locate faults accurately and to maintain the lines automatically and periodically in the DSLAMnetwork application.[0004] As defined by the ITU-T ADSL2 (G.992.3), Dual-ended Line Testing (DELT) is a technology for testing the stateof a line by setting test points at both sides of the line. The DELT technology is applicable to the test of the line diagnosismode. The test data deriving from DSL test performed through the DELT technology helps a maintenance engineeranalyze and find the location of the fault caused by crosstalk, radio frequency interference or a (bridge) tap, and discoverthe fault source.[0005] DELT may measure the line attenuation directly to obtain the length of the measured line. The methods forobtaining the line length through the DELT technology include attenuation measurement, and frequency/phase meas-urement. For example, to measure the length of a downstream line, a DSL transceiver at the central office may insertan excitation signal into the line, and the DSL transceiver in the subscriber-end device may measure the frequencyresponse, and therefore, the line length is calculated out according to the received result of the frequency response. Inanother example, the line length may be calculated out through test of the line attenuation.[0006] In the process of creating the present invention, the inventor finds at least the following defects in the DELTtechnology for measuring the line length in the related art:[0007] (1) The test mode in the related DELT technology is rough, for example, simple attenuation test, and frequency/phase test. If the line diameter is unknown, such tests involve a wide extent of errors, and the measured line length isnot precise.[0008] (2) The test objects are unitary. For example, the related DELT technology provides no method for calculatinga line diameter.
Summary of the Invention
[0009] A line measurement method and a measurement apparatus are provided in various embodiments of the presentinvention to measure both the diameter and the length of a line in the DELT test and improve the measurement precision.[0010] A line measurement method is provided in an embodiment of the present invention. The method includes:
obtaining data of relation between the line length and the insertion loss phase radian of the first-loop gauge and thesecond-loop gauge under a fixed frequency, and data of relation between the line length and the loop attenuationparameter value;defining a first length range according to two length values obtained by searching the data of relation between theline length and the insertion loss phase radian of the first-loop gauge and the second-loop gauge according to theinsertion loss phase radian of the measured loop gauge; and defining a second length range according to two lengthvalues by searching the data of relation between the line length and the loop attenuation parameter value of thefirst-loop gauge and the second-loop gauge according to the loop attenuation parameter value of the measuredloop gauge; anddetermining the boundary of the second length range close to the midpoint of the first length range, using a linelength value corresponding to the boundary close to the midpoint as a measured line length, and using the linediameter corresponding to the line length value as a measured line diameter.
[0011] Another line measurement method is provided in an embodiment of the present invention. The method includes:
obtaining data of relation between the line length and the insertion loss phase radian of the first-loop gauge and thesecond-loop gauge under a fixed frequency, and data of relation between the line length and the loop attenuation
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parameter value;defining a first length range according to two length values obtained by searching the data of relation between theline length and the insertion loss phase radian of the first-loop gauge and the second-loop gauge according to theinsertion loss phase radian of the measured loop gauge; defining a second length range and a third length rangeby using two length values obtained by searching the data of relation between the line length and the loop attenuationparameter value of the first-loop gauge and the second-loop gauge according to the loop attenuation parametervalue of the measured loop gauge as midpoints respectively, and defining the remaining length range between thesecond length range and the third length range as a fourth length range. The second length range and the thirdlength range correspond to the first-loop gauge and the second-loop gauge respectively, and the fourth length rangecorresponds to a hybrid line composed of the first-loop gauge and the second-loop gauge; andwhen the midpoint of the first length range belongs to the second length range, determining the line diametercorresponding to the second length range to be the first line diameter measured; when the midpoint of the first lengthrange belongs to the third length range, determining the line diameter corresponding to the third length range to bethe second line diameter measured; when the midpoint of the first length range belongs to the fourth length range,determining the hybrid line diameter corresponding to the fourth length range to be the measured line diameter.
[0012] Another line measurement method is provided in an embodiment of the present invention. The method includes:
obtaining data of relation between the line length and the uplink loop attenuation parameter value of the first-loopgauge and the second-loop gauge respectively, and data of relation between the line length and the downlink loopattenuation parameter value of the first-loop gauge and the second-loop gauge respectively;obtaining the first length value and the second length value respectively from the data of relation between the linelength and the uplink loop attenuation parameter value of the first-loop gauge and the second-loop gauge accordingto the loop attenuation parameter value of the measured loop gauge; and the third length value and the fourth lengthvalue respectively from the data of relation between the line length and the downlink loop attenuation parametervalue of the first-loop gauge and the second-loop gauge according to the loop attenuation parameter value of themeasured loop gauge; andobtaining an absolute value of difference between the first length value and the third length value, and an absolutevalue of difference between the second length value and the fourth length value, comparing the two absolute values,and using the diameter and the length of the line corresponding to the length values with a smaller absolute valueof difference as the measured line diameter and the measured length.
[0013] Another line measurement method is provided in an embodiment of the present invention. The method includes:
obtaining the insertion loss of a measured line;substituting, the theoretical values of the first insertion loss and the second insertion loss of a loop at a middledistance of the first-loop gauge and the second-loop gauge, as well as the insertion loss of the measured line, intoa function of the insertion loss and the line length under a fixed frequency to obtain the first optional line length andthe second optional line length;substituting the line diameter value and the length value of the first-loop gauge and the second-loop gauge into theinsertion loss function of the first-loop gauge and the second-loop gauge to obtain the first calculated value ofinsertion loss and the second calculated value of insertion loss; andobtaining a sum of errors between the insertion loss of the measured line and the first calculated value of insertionloss in all or some bands; and a sum of errors between the insertion loss of the measured line and the secondcalculated value of insertion loss in all or some bands; comparing the two sums of errors, and using the line lengthand the line diameter corresponding to the data with a smaller sum of errors as the measured line length and themeasured line diameter.
[0014] A measurement apparatus is provided in an embodiment of the present invention. The measurement apparatusincludes:
a storing unit, configured to: store the data of relation between the line length and the insertion loss phase radianof the first-loop gauge under a fixed frequency, and the data of relation between the line length and the loop attenuationparameter value; and store the data of relation between the line length and the insertion loss phase radian of thesecond-loop gauge under a fixed frequency, and the data of relation between the line length and the loop attenuationparameter value;a measuring unit, configured to obtain the insertion loss phase radian and the loop attenuation parameter value ofthe measured loop gauge;
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a searching unit, configured to: define a first length range according to the two length values; search the data ofrelation between the line length and the loop attenuation parameter value of the first-loop gauge and the second-loop gauge according to the loop attenuation parameter value of the measured loop gauge to obtain two lengthvalues obtained by searching the data of relation between the line length and the insertion loss phase radian of thefirst-loop gauge and the second-loop gauge according to the insertion loss phase radian of the measured loopgauge, and define a second length range according to the two length values; anda determining unit, configured to: determine the boundary of the second length range close to the midpoint of thefirst length range, use a line length value corresponding to the boundary close to the midpoint as a measured linelength, and use the line diameter corresponding to the line length value as a measured line diameter.
[0015] The foregoing technical solution shows that: The data of relation between the line length and the insertion lossphase radian, and data of relation between the line length and the loop attenuation parameter value of lines with variouspossible diameters are obtained beforehand; afterward, the insertion loss phase radian and the loop attenuation param-eter value are obtained according to the actual measured line, and the corresponding length values are obtained fromthe data of relation between the line length and the insertion loss phase radian and the data of relation between the linelength and the loop attenuation parameter value of lines with various diameters; subsequently, the errors of the linelengths of lines with various diameters are compared under specific parameter conditions such as the phase radian andloop attenuation parameter value; the line length and the line diameter with a smaller error are used as the line lengthand the line diameter of the measured loop gauge. Therefore, both line length and line diameter of the measured linecan be confirmed skillfully at the same time, and the measurement precision is improved, which facilitates the subsequentline maintenance and troubleshooting.
Brief Description of the Drawings
[0016] FIG. 1 is a flowchart of a measurement method provided in the first embodiment of the present invention;[0017] FIG. 2 is a flowchart of a measurement method provided in the second embodiment of the present invention;[0018] FIG. 3 shows a 2-port network in the second embodiment of the present invention;[0019] FIG. 4 shows a twisted pair transmission system in the second embodiment of the present invention;[0020] FIG. 5 shows the relation between Hlin(f) phase radian and frequency of AWG #24 and #26 lines in an em-bodiment of the present invention;[0021] FIG. 6 shows the relation between line length and phase radian under the fixed frequency of 1104 KHz;[0022] FIG. 7 shows the relation between line length and uplink LATN in an embodiment of the present invention;[0023] FIG. 8 is a flowchart of a line measurement method provided in the third embodiment of the present invention;[0024] FIG. 9 shows a hybrid line interval in an embodiment of the present invention;[0025] FIG. 10 is a flowchart of a line measurement method provided in the fourth embodiment of the present invention;[0026] FIG. 11 is a flowchart of a line measurement method provided in the fifth embodiment of the present invention;[0027] FIG. 12 is a schematic diagram of a measurement apparatus provided in the first embodiment of the presentinvention; and[0028] FIG. 13 is a schematic diagram of a measurement apparatus provided in the second embodiment of the presentinvention.
Detailed Description of the Invention
[0029] To make the technical solution, objectives and merits of the present invention clearer, the embodiments of thepresent invention are described below in detail with reference to accompanying drawings.[0030] One aspect of the present invention is a practical technology for calculating the line length and the line diameterby using DELT test data, and is a method for calculating the line length and the line diameter of the subscriber lineaccording to the test parameters defined in the relevant chapters in ADSL 2 (G.992.3) and ADSL2+ (G.992.5) formulatedby the ITU-T, and provides a reference basis for maintenance and troubleshooting of the subscriber line.[0031] A line measurement method is provided in the first embodiment of the present invention. As shown in FIG. 1,the method includes the following steps:[0032] Step 101: The data of relation between the line length and the insertion loss [Hlin(f)] phase radian of the first-loop gauge under a fixed frequency and the data of relation between the line length and the loop attenuation parametervalue are obtained. The data of relation between the line length and the Hlin(f) phase radian of the second-loop gaugeunder a fixed frequency and the data of relation between the line length and the loop attenuation parameter value areobtained.[0033] Step 102: The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge andthe second-loop gauge according to the Hlin(f) phase radian of the measured loop gauge is queried in order to obtain
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two length values, and a first length range is defined according to the two length values. The data of relation betweenthe line length and the loop attenuation parameter value of the first-loop gauge and the second-loop gauge accordingto the loop attenuation parameter value of the measured loop gauge is queried in order to obtain two length values, anda second length range is defined according to the two length values.[0034] Step 103: Boundary of the second length range close to the midpoint of the first length range is determined, aline length value corresponding to the boundary close to the midpoint is used as a measured line length, and the linediameter corresponding to the line length value is used as a measured line diameter.[0035] The foregoing embodiment shows that: The data of relation between the line length and the Hlin(f) phase radian,and data of relation between the line length and the loop attenuation parameter value of lines with various possiblediameters are obtained beforehand; afterward, the Hlin(f) phase radian and the loop attenuation parameter value areobtained according to the actual measured line, and the corresponding length values are obtained from the data ofrelation between the line length and the Hlin(f) phase radian and the data of relation between the line length and theloop attenuation parameter value of lines with various diameters, and the first length range and the second length rangeare obtained. As inferred from the related art, the first length range obtained from the data of relation between the phaseradian and the line length of the first-loop gauge and the second-loop gauge is less than the second length range, andis more precise. The midpoint of the first length range serves as a basis of judgment, the line length value correspondingto the boundary of the second length range close to the midpoint serves as a measured line length, and the line diametercorresponding to this line length value serves as a measured line diameter. Therefore, both the line length and the linediameter of the measured line can be confirmed skillfully at the same time, and the measurement precision is improved,which facilitates the subsequent line maintenance and troubleshooting.[0036] The line measurement method under the present invention is detailed below, taking a measured loop gaugeof a twisted pair as an example, and taking the twisted pairs of the first line diameter (AWG #24) and the second linediameter (AWG #26) as examples.[0037] FIG. 2 shows a line measurement method in the second embodiment of the present invention. In this embod-iment, the line length and the line diameter are calculated by using the Hlin(f) phase value and the loop attenuation(LATN) value in the test parameters. The method includes the following steps:[0038] Step 201: The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge undera fixed frequency and the data of relation between the line length and the loop attenuation parameter value are obtained.Yhe data of relation between the line length and the Hlin(f) phase radian of the second-loop gauge under a fixed frequencyand the data of relation between the line length and the loop attenuation parameter value are obtained.[0039] (1) The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge and thesecond-loop gauge is obtained under a fixed frequency.[0040] As defined in ITU-T ADSL2 (G.992.3), Hlin(f) is a function that reflects transmission features of a channel. Anequation between Hlin(f) and twisted pair feature parameters may be created by deducing the value RLCG model andthe ABCD parameters of the twisted pair.[0041] 1. RLCG model[0042] The twisted pair is a type of transmission line. Any transmission line has basic parameters such as resistance(R), inductance (L), and conductance (G), and such parameters are called RLCG parameters. The RLCG model usesthe RLCG parameters of a twisted pair to represent the channel features of the twisted pair. The RLCG model is alsoknown as a primary model of the twisted pair channel because it provides only the RLCG parameters of the twisted pairchannel rather than the transfer function of the twisted pair channel. As described below, the transfer function is deducedaccording to the RLCG parameters under the present invention.[0043] The numeric RLCG model of twisted pairs (AWG #24 and #26) is obtained through measurement of the curvefitting of the cables, and is applicable to all bands, including the VDSL band. Equations 1-4 are general equations of theRLCG:
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[0044] The parameters involved in the equations are listed in Table 1.
[0045] 2. Transmission constants and characteristic impedance of transmission lines[0046] According to the foregoing transmission line RLCG parameters, two common parameters may be obtained:transmission constant (λ) and characteristic impedance (Z0(f)), which can represent the voltage and the current alongthe transmission line. The transmission constant is:
[0047] The definition of a propagation constant is based on two basic assumed scenarios: (1) jωC>> G; and (2) jωL>>R when frequency f> 100 KHz. The following equations 6 and 7 may be deduced according to equation 5:
b 1.1529766 0.92930728g0 (Siemen / Hz * km) 0.23487476*10-12 4.3*10-8
ge 1.38 0.70
c∞ (nF / km) 50*10-9 49*10-9
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[0048] In the two equations above, α0 and β0 are constants. According to the RLCG model of the transmission line,the characteristic impedance is defined as:
[0049] 3. ABCD model of a 2-port network[0050] The ABCD model uses a 2-port network to represent the features of a twisted pair channel. The ABCD modelregards the twisted pair channel as a black box, and uses the input-output relation of the twisted pair channel to describethe characteristics of the twisted pair channel. This channel model is also known as a secondary model of the twistedpair channel. The ABCD parameters are generally obtained according to the RLCG parameters. According to the ABCDmodel of the channel, it is easy to calculate out important parameters such as the transfer function, characteristicimpedance, and input impedance of the twisted pair.[0051] For an ordinary 2-port network, its ABCD parameters are illustrated in FIG. 3.[0052] The corresponding mathematic description is:
[0053] For the twisted pair transmission system shown in FIG. 4, its ABCD parameters may be proved as:
[0054] If no loop (ZS is connected to ZL directly) exists, the voltage distributed onto the load is:
[0055] If a loop exists, voltage V1 may be simplified as:
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[0056] After I1 is substituted into the equation above according to the second basic ABCD equation, the equation is:
[0057] After I2 is replaced with V2/ZL according to the ohm law, the equation is:
[0058] According the above equation, V2 is:
[0059] Therefore, Hlin(f) is:
[0060] 4. Relation between Hlin(f) phase radian and line length[0061] After equation (11) is substituted into equation (17), the following may be obtained:
[0062] In FIG. 4, if the source impedance ZS, the characteristic impedance Z0, and the load impedance ZL match, andwhen f ≥ 100kHz , it is deemed that ZS = ZL ≈ Z0.Therefore, the above equation is simplified as:
[0063] After equation (5) is substituted into the above equation, the following equation is obtained:
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[0064] The following equation may be deduced from equation (20) and equation (7):
[0065] Therefore, when f is known, a linear relation exists between the Hlin(f) phase radian and the line length.[0066] Based on the Hlin(f) equation 18 above, the relation between the Hlin(f) phase radian and the frequency oflines with different diameters (AWG #24 and #26) may be emulated on a computer, as shown in FIG. 5.[0067] In FIG. 5, the Y axis represents phase radian, and the X axis represents frequency The original value of thephase is an irregular curve that changes periodically with the increase of the frequency. In FIG. 5, the phase radian isspread. That is, at an interval of 2 π , the value in the next phase period is shifted so that the phase value of the nextperiod is linked to that of the previous period. In this way, the phase radian takes on a straight line within the frequencyrange rather than an irregular curve which changes with the period. Such processing is helpful for observing and under-standing the relation between the phase radian, the frequency, and the line length.[0068] As shown in FIG. 5, the phase radian increases with the increase of the line length, and the difference betweenthe radian of the AWG #24 cable and the radian of the AWG #26 cable under the same distance is very small.[0069] FIG. 6 shows the relation between line length and phase radian under the fixed frequency of 1104 KHz, wherethe Y axis represents phase radian and the X axis represents line length.[0070] Taking the AWG #24 line and the AWG #26 line in FIG. 6 as examples, the ratio [K(1)] of the phase radian tothe line length within the range defined by f = 1104 KHz and L ∈ (1km, 6km) is calculated below:
[0071] Table 2 shows that the values of K#24 and K#26 are approximately constant, and their maximum fluctuation isapproximately 0.005%. This error is ignorable in the subsequent calculation. If the average value within L ∈ (1km, 6km)is used, the results are:
[0072] After the Hlin(f) value of the measured line is obtained, the length range (D1, D2) of the AWG #26 and #24 lines is:
Table 2: Ratio of phase radian to line lengthDistance L(m) 1000 2000 3000 4000 5000 6000K#24 -2.0347 -2.0347 -2.0347 -2.0348 -2.0348 -2.0348
[0073] Therefore, an estimated line length value is:
[0074] The difference between two lengths in the above length range is:
[0075] After the values of D1,D2 are substituted into the above equation, the following is obtained:
[0076] When ∠Hlin(f) ∈ (0,-13000) , the error between the result of equation 24 and the actual line length is:
[0077] After equation 27 and equation 23 are substituted into the above equation, the error is 1.65%.[0078] (2) The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge and thesecond-loop gauge is obtained under a fixed frequency.[0079] As defined by the ITU-T ADSL2 (G.992.3) standard, the LATN is a parameter that reflects loop attenuation,and is a difference between the transmit power and the receive power (measured in dB). The LATN is defined below:
[0080] FIG. 7 shows the relation between the line length and the uplink LATN, where the Y axis represents LATN and
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the X axis represents line length. In the straight line fitting, the value of LATN in the uplink direction is in a linear relationwith the line length.[0081] The ratio [M(1)] of LATN to line length is defined as:
[0082] Table 3 lists the values of M(1) calculated under different lengths according to equation 29.
[0083] Table 3 shows that the maximum fluctuation of the M value is 8%. The error caused by such fluctuation isignorable in the subsequent calculation specific to different line diameters. The M value of the same line diameter changesslowly in the test interval, and is approximately constant. If the average of the M values is used, the results are:
[0084] If it is known that the measured line is either AWG #24 or #26, after the uplink LATN of the measured line ismeasured, the length range (L1,L2) of the line can be deduced:
[0085] The difference between two lengths in the above length range is:
[0086] After L1,L2 are substituted into the above equation, the following is obtained:
Table 3: Ratio of uplink LATN to line lengthDistance L(m) 1000 2000 3000 4000 5000 6000M#24 0.0136 0.0124 0.0116 0.0110 0.0106 0.0103
M#26 0.0171 0.0157 0.0148 0.0142 0.0138 0.0135
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[0087] The error is:
[0088] After equation 32 and equation 34 are substituted into equation 35, the error is 11.13%.[0089] The measured loop attenuation parameter value of the first-loop gauge and the second-loop gauge may be anuplink loop attenuation parameter value obtained by measuring the first-loop gauge and the second-loop gauge, or adownlink loop attenuation parameter value obtained by measuring the first-loop gauge and the second-loop gauge.[0090] According to equation 21, the following is known:
[0091] According to equation 20, the following may be deduced:
[0092] Therefore,
[0093] That is,
[0094] Equation 29 shows that the LATN value increases with the increase of D.[0095] Equation 26 and equation 33 show that with respect to the value range of ∠(Hlin) and LATN:
[0096] Therefore,
[0097] It is inferred that the fluctuation of ∠(Hlin) as against line diameters (AWG #24 and #26) is far less than the
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fluctuation of LATN as against line diameters (AWG #24 and #26). It is understandable that the line length obtained fromthe data of relation between the phase radian and the line length involves a smaller error and is more precise.[0098] Step 202: The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge andthe second-loop gauge according to the Hlin(f) phase radian of the measured loop gauge is queried to obtain two lengthvalues, and a first length range is defined according to the two length values. The data of relation between the line lengthand the loop attenuation parameter value of the first-loop gauge and the second-loop gauge according to the loopattenuation parameter value of the measured loop gauge is queried to obtain two length values, and a second lengthrange is defined according to the two length values, as detailed below:[0099] Based on equation 18, a table is created to reflect the relation between line length and phase radian of theAWG #24 and #26 lines in the case of frequency f = 1104 KHz. In the able, the line length may be 0-6 Km (or variableaccording to the actual conditions), and 5 m is the minimum step. The minimum step of the line length determines thecalculated minimum error of the line, and may vary as required. After the measured line Hlin (f) is obtained, its phaseradian may be calculated out. The length range (D1,D2) of the AWG #26 and #24 lines may be found through tablelookup. In this embodiment, this length range is called the first length range.[0100] Based on equation 29, a table is created to reflect the relation between the line length and the uplink/downlinkLATN value of the AWG #24 and #26 lines. The line length in the table is generally 0-6 Km, and 5 m is the minimumstep. The minimum step of the line length determines the calculated minimum error of the line, and may vary as required.After the uplink LATN of the measured line is obtained, the length range (L1,L2) of the AWG #24 and #26 lines may befound through table lookup. In this embodiment, this length range is called the second length range.[0101] In this way, a smaller first length range (D1,D2) of the line is determined first according to the ∠(Hlin) information,and then a larger second length range of the line (L1,L2) is determined according to the LATN.[0102] Step 203: The boundary of the second length range close to the midpoint of the first length range is determined,a line length value corresponding to the boundary close to the midpoint is used as a measured line length, and the linediameter corresponding to the line length value is used as a measured line diameter, as detailed below:
[0103] is compared with If is greater than
it is indicated that the line length is closer to the boundary of the second length range (L2), and
therefore, the line diameter is determined as AWG #24. If is smaller than it is
indicated that the line length is closer to the boundary of the first length range (L1), and therefore, the line diameter is
determined as AWG #26. This method may be used to determine a single line diameter.[0104] The fluctuation of ∠(Hlin) as against line diameters (AWG #24 and #26) is far less than the fluctuation of theLATN as against line diameters (AWG #24 and #26) if the line length is the same. Therefore, either the length D1 or thelength D2 determined by ∠(Hlin) is generally selected according to the line diameter determined in step 203, so that amore precise line length may be obtained.[0105] A line measurement method is provided in the third embodiment of the present invention. As shown in FIG. 8,the method includes the following steps:[0106] Step 801: The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge undera fixed frequency, and the data of relation between the line length and the loop attenuation parameter value are obtained..The data of relation between the line length and the Hlin(f) phase radian of the second-loop gauge under a fixed frequencyand the data of relation between the line length and the loop attenuation parameter value are obtained.[0107] Step 802: The data of relation between the line length and the Hlin(f) phase radian of the first-loop gauge andthe second-loop gauge according to the Hlin(f) phase radian of the measured loop gauge is queried to obtain two lengthvalues, and a first length range is defined according to the two length values. The data of relation between the line lengthand the loop attenuation parameter value of the first-loop gauge and the second-loop gauge according to the loopattenuation parameter value of the measured loop gauge is queridd to obtain two length values, a second length rangeand a third length range are defined by using the two length values as midpoints respectively, and the remaining lengthrange between the second length range and the third length range a fourth length range is defined. The second lengthrange and the third length range correspond to the first-loop gauge and the second-loop gauge respectively, and thefourth length range corresponds to a hybrid line composed of the first-loop gauge and the second-loop gauge.[0108] Step 803: If the midpoint of the first length range belongs to the second or third length range, the line diametercorresponding to the second or third length range is determined as the measured line diameter. If the midpoint of the
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first length range belongs to the fourth length range, the hybrid line diameter corresponding to the fourth length rangeis determined as the measured line diameter.[0109] This embodiment is about a method for measuring a hybrid line. In practice, the measured line may be splicedfrom the lines with two or more line diameters. Therefore, as against the measured line with only one line diameter, it isnecessary to provide multiple length intervals of possible line lengths. FIG. 9 shows a hybrid line interval, where themeasured line is a spliced subscriber line that involves two line diameters. The range determined by L1,L2 may be dividedinto three intervals.[0110] Therefore, a standard error may be calculated out according to equation 28 and the test error (e%):
[0111] A judgment range is estimated:[0112] (1) Judgment interval of AWG #26:
[0113] (2) Judgment interval of AWG #24:
[0114] (3) Judgment interval of a hybrid line:
[0115] The line diameter and the line length are determined according to the interval that covers
[0116] An equation that involves Hlin may be created according to the RLCG parameters of the line diameter. Accordingto steps 801-803, the line length and the line diameter are calculated out, and a judgment is made about whether theline diameter is a hybrid line diameter.[0117] FIG. 10 shows a line measurement method in the fourth embodiment of the present invention. In this embod-iment, the line length and the line diameter are calculated by using the uplink value and the downlink value of the LATNin the test parameters. The method includes the following steps:[0118] Based on equation 29, find that the fluctuation of the LATN in the uplink direction of a loop gauge is differentfrom the fluctuation of the LATN in the downlink direction of the same loop gauge. Therefore, the length and the diameterof a line can be calculated out after the uplink LATN value and the downlink LATN value of the line are measured.[0119] Step 1001: The data of relation between the line length and the uplink loop attenuation parameter value of thefirst-loop gauge and the data of relation between the line length and the downlink loop attenuation parameter value ofthe first-loop gauge are obtained. The data of relation between the line length and the uplink loop attenuation parametervalue of the second-loop gauge and the data of relation between the line length and the downlink loop attenuationparameter value of the second-loop gauge are obtained.[0120] Based on equation 29, a table is created to reflect the relation between the line length and the uplink/downlinkLATN value of the AWG #24 and #26 lines. The line length in the table is generally 0-6 Km, and 5 m is the minimumstep. The minimum step of the line length determines the calculated minimum error of the line, and may vary as required.[0121] Step 1002: The first length value and the second length value respectively from the data of relation betweenthe line length and the uplink loop attenuation parameter value of the first-loop gauge and the second-loop gauge areobtained according to the loop attenuation parameter value of the measured loop gauge; and the third length value andthe fourth length value respectively from the data of relation between the line length and the downlink loop attenuation
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parameter value of the first-loop gauge and the second-loop gauge are obtained according to the loop attenuationparameter value of the measured loop gauge.[0122] After the uplink LATN and the downlink LATN of the measured line are obtained, the lengths (D1,D2) of theAWG #26 and #24 lines may be found through table lookup. After the downlink LATN of the measured line are obtained,the lengths (D4,D3) of the AWG #26 and #24 lines may be found through table lookup.[0123] Step 1003: An absolute value of difference between the first length value and the third length value and anabsolute value of difference between the second length value and the fourth length value are obtained, the two absolutevalues are compared, and the diameter and the length of the line corresponding to the length values with a smallerabsolute value of difference are used as the measured line diameter and the measured length.[0124] The absolute value |D1-D4| is compared with the absolute value |D2-D3|. The diameter and the length corre-sponding to the smaller absolute value are the diameter and the length of the actual line.[0125] In this embodiment, only one parameter value is measured so that the measurement is easier.[0126] As shown in FIG. 11, a line measurement method is provided in the fifth embodiment of the present invention.In this embodiment, the line length and the line diameter are calculated by using the Hlog(f) value in the test parameters.The method includes the following steps:[0127] Step 1101: The logarithmic value Hogtest of the insertion loss of the measured line is obtained.[0128] Step 1102: The theoretical logarithmic value Hlogref 24 of the first insertion loss of the loop at a middle distanceof the first-loop gauge and the logarithmic value Hlogtest of the insertion loss of the measured line are substituted intoa linear function of the logarithmic value Hlog(f) of the insertion loss and the line length under a fixed frequency to obtainan optional line length Ltest24. The theoretical logarithmic valueHlogref 26 of the second insertion loss of the loop at a middle distance of the second-loop gauge and Hlogtest of themeasured line are substituted into a linear function of Hlog(f) and the line length under a fixed frequency to obtain anoptional line length Ltest26.[0129] Equation 37 |Hlin(f)|dB ∝ L shows that: When frequency f > 100 KHz, an approximate linear relation existsbetween the Hlog(f) and the line length L under the same frequency:
[0130] First, the Hlogtest parameter of the line is obtained. Then theoretical values of Hlogref 24 and Hlogref 26 of theloop at a middle distance (for example, 2 km) of the AWG #24 line and #26 line are selected as a reference loop, andthe following equations are obtained on the basis of equation 42:
[0131] The measured Hlogtest parameter into equation 43 and equation 44 is substituted to obtain length values Ltest24and Ltest26 under two different line diameters.[0132] Step 1103: The diameter value of the first-loop gauge and the line length Ltest24 are substituted into the insertionloss function Hlin(f) of the first-loop gauge, and a logarithmic operation is performed to obtain Hlogtest24. The diametervalue of the second-loop gauge and the line length Ltest24 are substituted into the insertion loss function Hlin(f) of thesecond-loop gauge, and then a logarithmic operation is performed to obtain Hlogtest26.[0133] The following variance sums is obtained in all bands:
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[0134] Step 1104: A sum of mean square errors, a variance sum, or a difference sum of Hlogtest and Hlogtest24 isobtained in all bands or some bands. A sum of mean square errors, a variance sum, or a difference sum of Hlogtest andHlogtest26 is obtained in all bands or some bands. The error sums of the foregoing data are compared, and the line lengthand the line diameter corresponding to the data with a smaller error sum are used as the measured line length and themeasured line diameter.[0135] For example, error24 is compared with error26, and the line diameter and the line length corresponding to thesmaller error are the diameter and the length of the actual line.[0136] In more embodiments, it is not necessary to adopt the logarithmic form of the insertion loss function, but adoptthe insertion loss function value itself for calculation. In this way, the linear function of the logarithmic value Hlog(f) ofthe insertion loss and the line length is changed to the function of the logarithmic value Hlog(f) of the insertion loss andthe line length.[0137] It is understandable to those skilled in the art that all or part of the steps of the line measurement method inthe foregoing embodiments may be implemented by hardware instructed by a program. The program may be stored ina computer-readable storage medium. When being executed, the program includes the contents of all the foregoingembodiments of the method under the present invention. The storage medium mentioned above may be a Read-OnlyMemory/Random Access Memory (ROM/RAM), a magnetic disk, a compact disk, and so on.[0138] A measurement apparatus is also provided in the first embodiment of the present invention. As shown in FIG.12, the measurement apparatus includes:
a storing unit, configured to: store the data of relation between the line length and the Hlin(f) phase radian of thefirst-loop gauge under a fixed frequency, and store the data of relation between the line length and the loop attenuationparameter value; store the data of relation between the line length and the Hlin(f) phase radian of the second-loopgauge under a fixed frequency, and store the data of relation between the line length and the loop attenuationparameter value;a measuring unit, configured to obtain the Hlin(f) phase radian and the loop attenuation parameter value of themeasured loop gauge;a searching unit, configured to: search the data of relation between the line length and the Hlin(f) phase radian ofthe first-loop gauge and the second-loop gauge according to the Hlin(f) phase radian of the measured loop gaugeto obtain two length values, and define a first length range according to the two length values; search the data ofrelation between the line length and the loop attenuation parameter value of the first-loop gauge and the second-loop gauge according to the loop attenuation parameter value of the measured loop gauge to obtain two lengthvalues, and define a second length range according to the two length values; anda determining unit, configured to: determine the boundary of the second length range close to the midpoint of thefirst length range, use a line length value corresponding to the boundary close to the midpoint as a measured linelength, and use the line diameter corresponding to the line length value as a measured line diameter.
[0139] The first embodiment of the present invention shows that: The data of relation between the line length and theHlin(f) phase radian, and data of relation between the line length and the loop attenuation parameter value of lines withvarious possible diameters are obtained beforehand; afterward, the Hlin(f) phase radian and the loop attenuation pa-rameter value are obtained according to the actual measured line, and the corresponding length values are obtainedfrom the data of relation between the line length and the Hlin(f) phase radian and the data of relation between the linelength and the loop attenuation parameter value of lines with various diameters, and the first length range and the secondlength range are obtained. As inferred from the related art, the first length range obtained from the data of relationbetween the phase radian and the line length of the first-loop gauge and the second-loop gauge is less than the secondlength range, and is more precise. The midpoint of the first length range serves as a basis of judgment, the line lengthvalue corresponding to the boundary of the second length range close to the midpoint serves as a measured line length,
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and the line diameter corresponding to this line length value serves as a measured line diameter. Therefore, both theline length and the line diameter of the measured line can be confirmed skillfully at the same time, and the measurementprecision is improved, which facilitates the subsequent line maintenance and troubleshooting.[0140] A measurement apparatus is also provided in the second embodiment of the present invention. As shown inFIG. 13, the measurement apparatus includes:
a storing unit, configured to: store the data of relation between the line length and the uplink loop attenuationparameter value of the first-loop gauge, and store the data of relation between the line length and the downlink loopattenuation parameter value of the first-loop gauge; store the data of relation between the line length and the uplinkloop attenuation parameter value of the second-loop gauge, and store the data of relation between the line lengthand the downlink loop attenuation parameter value of the second-loop gauge;a measuring unit, configured to obtain the loop attenuation parameter value of the measured loop gauge;a searching unit, configured to: obtain the first length value and the second length value respectively from the dataof relation between the line length and the uplink loop attenuation parameter value of the first-loop gauge and thesecond-loop gauge according to the loop attenuation parameter value of the measured loop gauge; and obtain thethird length value and the fourth length value respectively from the data of relation between the line length and thedownlink loop attenuation parameter value of the first-loop gauge and the second-loop gauge according to the loopattenuation parameter value of the measured loop gauge; anda determining unit, configured to: after obtaining an absolute value of difference between the first length value andthe third length value and obtaining an absolute value of difference between the second length value and the fourthlength value, compare the two absolute values, and use the diameter and the length of the line corresponding tothe length values with a smaller absolute value of difference as the measured line diameter and the measured length.
[0141] It is worthy of attention that: The storing unit, the measuring unit, the searching unit, and the determining unitof the measurement apparatus in the first embodiment of the present invention may be integrated in one processingmodule. By analogy, all the units in the measurement apparatus in the second embodiment of the present invention mayalso be integrated in one processing module; or, any two or more units in the foregoing embodiments may be integratedinto one processing module.[0142] A measurement apparatus is also provided in the third embodiment of the present invention. The measurementapparatus includes:
an obtaining unit, configured to: obtain data of relation between the line length and the insertion loss phase radianof the first-loop gauge and the second-loop gauge under a fixed frequency, and obtain data of relation between theline length and the loop attenuation parameter value;a searching unit, configured to: search the data of relation between the line length and the insertion loss phaseradian of the first-loop gauge and the second-loop gauge according to the insertion loss phase radian of the measuredloop gauge to obtain two length values, and define a first length range according to the two length values; searchthe data of relation between the line length and the loop attenuation parameter value of the first-loop gauge and thesecond-loop gauge according to the loop attenuation parameter value of the measured loop gauge to obtain twolength values, define a second length range and a third length range by using the two length values as midpointsrespectively, and define the remaining length range between the second length range and the third length range asa fourth length range, where the second length range and the third length range correspond to the first-loop gaugeand the second-loop gauge respectively, and the fourth length range corresponds to a hybrid line composed of thefirst-loop gauge and the second-loop gauge; anda determining unit, configured to: when the midpoint of the first length range belongs to the second length range,determine the line diameter corresponding to the second length range to be the first line diameter measured; whenthe midpoint of the first length range belongs to the third length range, determine the line diameter correspondingto the third length range to be the second line diameter measured; when the midpoint of the first length range belongsto the fourth length range, determine the hybrid line diameter corresponding to the fourth length range to be themeasured line diameter.
[0143] A measurement apparatus is also provided in the fourth embodiment of the present invention. The measurementapparatus includes:
an insertion loss obtaining unit, configured to obtain the insertion loss of the measured line;a calculating unit, configured to: substitute the theoretical values of the first insertion loss and the second insertionloss of a loop at a middle distance of the first-loop gauge and the second-loop gauge, as well as the insertion lossof the measured line, into a function of the insertion loss and the line length under a fixed frequency to obtain the
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first optional line length and the second optional line length; and, substitute the line diameter values and the lengthvalues of the first-loop gauge and the second-loop gauge into the insertion loss function of the first-loop gauge andthe second-loop gauge to obtain the first calculated value of insertion loss and the second calculated value ofinsertion loss; anda determining unit, configured to: obtain a sum of errors between the insertion loss of the measured line and thefirst calculated value of insertion loss in all or some bands; obtain a sum of errors between the insertion loss of themeasured line and the second calculated value of insertion loss in all or some bands; compare the two sums oferrors, and use the line length and the line diameter corresponding to the data with a smaller sum of errors as themeasured line length and the measured line diameter.
[0144] It is worthy of attention that the units of the measurement apparatus in the embodiments of the present inventionmay be implemented through hardware, or, if applicable, through software function modules. Accordingly, the embodi-ments of the present invention may be sold or used as a stand-alone product, and, if applicable, may be stored in acomputer-readable storage medium for sale or use.[0145] To sum up, the present invention provides at least the following benefits:[0146] (1) The line length and line diameter may be determined concurrently within the testable range of the DELT,and the testable length range is wide. Generally, for an AWG #26 line, the length range testable by the DELT is 0-6000 m.[0147] (2) The precision of calculating the length and determining the diameter is high. Because the line diameter isdetermined first, and then the line length is determined according to the features of the line diameter, the precision is high.[0148] (3) A judgment can be made about whether the line is a hybrid line.[0149] (4) The application scope is wide. The DELT parameters Hlin, Hlog, and LATN, or any combination thereofmay serve as the line measurement parameters.[0150] Detailed above are a line measurement method and a measurement apparatus provided in the embodimentsthe present invention. Although the invention has been described through some exemplary embodiments, the inventionis not limited to such embodiments. It is apparent that those skilled in the art can make various modifications and variationsto the invention without departing from the scope of the invention.
Claims
1. A line measurement method, comprising:
respectively obtaining data of relation between a line length and an insertion loss phase radian of a first-loopgauge and a second-loop gauge under a fixed frequency, and data of relation between the line length and aloop attenuation parameter value;defining a first length range according to two length values obtained by searching the data of relation betweenthe line length and the insertion loss phase radian of the first-loop gauge and the second-loop gauge accordingto the insertion loss phase radian of a measured loop gauge ; and defining a second length range according totwo length values obtained by searching the data of relation between the line length and the loop attenuationparameter value of the first-loop gauge and the second-loop gauge according to the loop attenuation parametervalue of the measured loop gauge; anddetermining the boundary of the second length range which is close to a midpoint of the first length range, usinga line length value corresponding to the boundary close to the midpoint as a measured line length, and usinga line diameter corresponding to the line length value as a measured line diameter.
2. The method according to claim 1, wherein the measured loop attenuation parameter value of the first-loop gaugeand the second-loop gauge is an uplink or downlink loop attenuation parameter value obtained by measuring thefirst-loop gauge and the second-loop gauge.
3. The method according to the method 1, wherein using the line length value corresponding to the boundary close tothe midpoint as the measured line length refers to:
determining the boundary of the second length range close to the midpoint, selecting the boundary of the firstlength range close to the determined boundary of the second
length range, and using the line length value corresponding to the selected boundary of the first length range as themeasured line length.
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4. A line measurement method, comprising:
respectively obtaining data of relation between a line length and an insertion loss phase radian of a first-loopgauge and a second-loop gauge under a fixed frequency, and data of relation between the line length and aloop attenuation parameter value;defining a first length range according to the two length values obtained by searching the data of relation betweenthe line length and the insertion loss phase radian of the first-loop gauge and the second-loop gauge accordingto the insertion loss phase radian of a measured loop gauge; defining a second length range and a third lengthrange by using two length values obtained by searching the data of relation between the line length and theloop attenuation parameter value of the first-loop gauge and the second-loop gauge according to the loopattenuation parameter value of the measured loop gauge as midpoints respectively, and defining a remaininglength range between the second length range and the third length range as a fourth length range, wherein thesecond length range and the third length range correspond to the first-loop gauge and the second-loop gaugerespectively, and the fourth length range corresponds to a hybrid line composed of the first-loop gauge and thesecond-loop gauge; andwhen a midpoint of the first length range belongs to the second length range, determining a line diametercorresponding to the second length range to be a first line diameter measured; when the midpoint of the firstlength range belongs to the third length range, determining the line diameter corresponding to the third lengthrange to be the second line diameter measured; when the midpoint of the first length range belongs to the fourthlength range, determining a hybrid line diameter corresponding to the fourth length range to be a measured linediameter.
5. A line measurement method, comprising:
obtaining data of relation between a line length and an uplink loop attenuation parameter value of a first-loopgauge and a second-loop gauge respectively, and data of relation between the line length and a downlink loopattenuation parameter value of the first-loop gauge and the second-loop gauge respectively;obtaining a first length value and a second length value respectively from the data of relation between the linelength and the uplink loop attenuation parameter value of the first-loop gauge and the second-loop gaugeaccording to a loop attenuation parameter value of a measured loop gauge; and a third length value and a fourthlength value respectively from the data of relation between the line length and the downlink loop attenuationparameter value of the first-loop gauge and the second-loop gauge according to the loop attenuation parametervalue of the measured loop gauge; andobtaining an absolute value of difference between the first length value and the third length value, and anabsolute value of difference between the second length value and the fourth length value, comparing the twoabsolute values, and using a diameter and a length of the line corresponding to the length values with a smallerabsolute value of difference as a measured line diameter and a measured length.
6. A line measurement method, comprising:
obtaining an insertion loss of a measured line;substituting theoretical values of a first insertion loss and a second insertion loss of a loop at a middle distanceof a first-loop gauge and a second-loop gauge, as well as an insertion loss of the measured line, into a functionof insertion loss and line length under a fixed frequency to obtain a first optional line length and a second optionalline length;substituting a line diameter value and a length value of the first-loop gauge and the second-loop gauge into aninsertion loss function of the first-loop gauge and the second-loop gauge to obtain a first calculated value of theinsertion loss and a second calculated value of the insertion loss; andobtaining a sum of errors between the insertion loss of the measured line and the first calculated value of theinsertion loss in all or some bands; and a sum of errors between the insertion loss of the measured line and thesecond calculated value of the insertion loss in all or some bands; comparing the two sums of errors, and usingthe line length and a line diameter corresponding to the data with a smaller sum of errors as a measured linelength and a measured line diameter.
7. The method according to claim 6, wherein the sum of errors is a sum of mean square errors, a variance sum, or adifference sum.
8. A measurement apparatus, comprising:
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a storing unit, configured to: store data of relation between a line length and an insertion loss phase radian ofa first-loop gauge under a fixed frequency, and store data of relation between the line length and a loop attenuationparameter value; store data of relation between a line length and an insertion loss phase radian of a second-loop gauge under a fixed frequency, and store the data of relation between the line length and the loop attenuationparameter value;a measuring unit, configured to obtain an insertion loss phase radian and a loop attenuation parameter valueof a measured loop gauge;a searching unit, configured to: define a first length range according to two length values obtained by searchingthe data of relation between the line length and the insertion loss phase radian of the first-loop gauge and thesecond-loop gauge according to the insertion loss phase radian of the measured loop gauge; and define asecond length range according to two length values by searching the data of relation between the line lengthand the loop attenuation parameter value of the first-loop gauge and the second-loop gauge according to theloop attenuation parameter value of the measured loop gauge; anda determining unit, configured to: determine the boundary of the second length range close to a midpoint of thefirst length range, use a line length value corresponding to the boundary close to the midpoint as a measuredline length, and use a line diameter corresponding to the line length value as a measured line diameter.
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REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the Europeanpatent document. Even though great care has been taken in compiling the references, errors or omissions cannot beexcluded and the EPO disclaims all liability in this regard.
