CN101071659A - XDSL cable - Google Patents

Abstract

xDSL cable comprising a plurality of stranded groups (4) of individually insulated copper conductors (2) inserted in a sheath (5), where conductors (2) have a copper diameter of 0.4 +/- 0.05 mm and the PSACR of the cable (1) is more than or equal 30dB at 1MHz for a length of 1km, or conductors (2) have a copper diameter of 0.5 +/- 0.05 mm and the PSACR of the cable (1) is more than or equal 34dB at 1MHz for a length of 1km; stranded groups (4) have a twist lay length of more than or equal 20 mm.

Description

XDSL cable

Technical field

Technical field of the present invention is the telephone cable field.Especially, the present invention relates to the cable that is used for transfer of data and the xDSL system is optimized.

Background technology

Now, main incident is the introducing of XDSL (abbreviating xDSL as) in the telecommunications.XDSL is a new technology of using existing telephone network and cable to transmit data with bit rate between interconnected users.All traditional telephone operators have the telephone cable technical standard of setting up for a long time, and it defines the specified and minimum requirements of the cable in the network that is installed in them.These technical standards are set up at first so that satisfied telephone service to be provided, and its frequency range is limited to 3400Hz, perhaps reaches 4000Hz in some networks sometimes.

All cables manufacturing merchants that these operators are sold in plan optimize their product so that satisfy these minimum requirements with the low cost of most probable, that is, by tightening that foozle only satisfies minimum requirements and the cable that too many waste product can not occur or be rejected by the inspector of operator.

The problem of xDSL is to keep the data bit rates of maximum possible to deal with more and more harsher now application.The xDSL system allows the transmission of some Mbit/s data.For this reason, they use the frequency band that reaches some MHz.Wish that state-of-the-art xDSL system can operate reaching under the frequency of 30MHz, even distance is shorter.It is also conceivable that higher frequency.The scope of using is significantly different with phone application.

Though xDSL declares system supply side their system and is designed to almost be applicable to any cable that it is suspicious that two factors make this declare:

-xDSL system has obtained success, and its " filling rate (fill rate) " (quantity that is used for the right xDSL system of cable same bundle) of bringing is more much higher than what think at first.In fact, in building, equipment is used for being connected to the cable xDSL filling of maintenance 100% usually of xDSL operator modulator-demodulator (DSLAM).

Competition between the-operator has forced them that " unlimited xDSL " is provided, and promptly operate in the xDSL under the maximum possible bit rate, and their initial service is the software that is confined to much smaller value.Therefore provide more that bit rate is a competitive advantage to operator, even make and now provide TV, especially under the situation of HDTV (High-Definition Television) by the IP that needs bit rate.

The major defect of the telephone cable of prior art comes from them and is optimized for low-frequency relatively this fact.Therefore to the needs of the replacement cables that is exclusively used in xDSL, it can keep the bit rate that increases.When addressing this problem, up to the present be known that the technology that is derived from data transmission world (local area network (LAN)) that adopts.

The technical standard of cable no matter be indoor or outdoor cable, has very strict requirement to two traditional parameters: crosstalk and return loss requirement.In both cases minimum requirements be set to higher, and test frequency regulation De Genggao.But this way proof is not effectively and is uneconomic, because obtainable hardly trickle improvement has shown too high cost.

US2005/173144 discloses the cable with stranded conductor that uses in digital system.Cable use simultaneously have 10 and 80mm between a series of pitches of minimum and maximum value, and conductor thickness is that 2.0-2.2 times of conductor diameter, dielectric constant are 1.87 conductor insulation body.The particular order of pitch make reduce and Digital Transmission in about the improvement of crosstalk problem.

This piece document is at strengthening the same problem of digital data transfer with the electrical property of telecommunication cable.Used diverse method, wherein changed pitch according to geometric progression.

Because obtaining the pitch of this geometric progression is a manufacture process that cost is high, therefore can not be accepted economically.The substitute is, the present invention uses the habitual constant pitch of field of cables.

Summary of the invention

The present invention proposes and is intended to address this problem.

The purpose of this invention is to provide a kind of xDSL cable, comprise in a plurality of insertion sheaths, by stranded group of constituting of copper conductor of insulation alone, wherein the diameter of copper conductor be 0.4+/-0.05mm and under the 1MHz frequency, when 1km is long the PSACR of cable more than or equal to 30dB, perhaps the diameter of copper conductor be 0.5+/-0.05mm and under the 1MHz frequency, when 1km is long the PSACR of cable more than or equal to 34dB, and each stranded group constant twisting pitch that has more than or equal to 20mm.

The solution that proposes has advantageously provided such possibility, than the cable (data type) that envisions and most of occasion is used, can make the cable that the xDSL performance significantly improves with much lower cost.

And it provides the possibility of remarkable improvement xDSL bit rate.Such cable advantageously makes the xDSL traffic have than existing cable up to 100% bit rate, especially long apart from the time.

And the cable that these performances are improved has also satisfied the technical standard of existing telephone operator.Consider that operator changes the needed time of its technical standard, this is a very big advantage.

The conductor of these cables can become strand or four lines stranded.

According to another characteristics of the present invention, for the conductor of quad, the ratio of insulation diameter and copper conductor diameter is more than or equal to 1.8.

According to another characteristics of the present invention, for the conductor of paired marshalling, the ratio of insulation diameter and copper conductor diameter is more than or equal to 1.9.

According to another characteristics of the present invention, cable also is included in described sheath and the described shielding of respectively organizing between the conductor.

According to another characteristics of the present invention, cable also is included in described sheath and the described filler of respectively organizing between the conductor that blocks water.

According to another characteristics of the present invention, copper conductor is by following insulated with material: foam, foam-epidermis or epidermis-foam-epidermis polyolefin (for example, polyethylene or polypropylene).

According to another characteristics of the present invention, sheath is made by following material: PVC, PE, the non-halogen compound of light cigarettes.

According to another characteristics of the present invention, shielding is made by following material: Al, Al+PET.

According to another characteristics of the present invention, each group is shielded separately.

Another object of the present invention provides a kind of method of definite xDSL cable, and it may further comprise the steps:

A) the minimum required bit rate and the minimum PSACR of qualification cable,

B) maximum of selection copper conductor diameter,

C) minimum value of the constant twisting pitch of selection,

According to another characteristics of the present invention, this method also comprises the step of the minimum value of the ratio of selecting insulation diameter and copper conductor diameter.

Description of drawings

By below in conjunction with the given detailed description of accompanying drawing, other characteristics of the present invention, details and advantage can become more apparent, wherein:

Fig. 1 is the longitudinal profile view according to cable of the present invention;

Fig. 2 is the amplification detail drawing of conductor;

Fig. 3 is the circuit that is used for limiting the operation decay;

Fig. 4 is the contrast table of prior art and first kind cable of the present invention;

Fig. 5 is the contrast table of prior art and the present invention's second class cable;

Fig. 6 illustrates the bit rate-length property comparison of existing cable and cable of the present invention;

Fig. 7,8 illustrates the two kinds of different layouts and their wire harness of many logarithms cable with sectional view.

Embodiment

According to Fig. 1, telephone cable 1 generally includes a plurality of conductors that are made of copper usually 2.Each conductor 2 each freedom shows to amplify detail drawing among Fig. 2 around insulator 3 insulation.Insulated electric conductor 2 combination in groups 4.Carry out stranded alone for every group 4.Gather bunchy or concentric layer for a plurality of groups 4 to form cable 1.Each bundle can be screened or not screen.Cable 1 can comprise a large amount of conductor 2, reaches 64 independent conductors or more.These a plurality of conductors insert in the sheath 5 of the described conductor 2 of protection.

What know is to increase the copper diameter of conductor 2 so that better transmission property to be provided.But copper is noble metal, and need carry out economic consideration and do not have the cable with too large diameter conductor 2 so that do not produce.And cable 1 according to the present invention is intended to replace gradually existing telephone network cables.It is 0.4 or 0.5mm that this existing cable is designed to the copper diameter together with all ambient network or service equipment.For these two kinds of reasons, economic and custom, cable 1 of the present invention must preferably remain in the identical scope.

Main thought of the present invention is: crosstalk (crosstalk) is to implement to spend the effective ways that big feature (very slow manufacturing speed) is not again the raising performance.Decay by reducing cable (in theoretical and test) shows much higher gain in bit rate (gains in bit rate).This can be by increasing cable impedance (cable ' s impedance) obtain, it is the anti-intuition solution of data cable because return loss has increased, echo (echo) has produced, and has produced the impedance loss that do not match.

Very anti-echoloss of xDSL system and echo be not because they use identical wave band to transmit at both direction usually.In addition, return loss and the echo that (promptly away from modulator-demodulator) produces in the network depths covered in high loss effectively.

Loss is not a problem for the xDSL system because long cable length, impedance match: in other words, reducing of loss is not to compensate the loss that do not match.In data cable, typically be limited to 100 meters length, this is not this case.With reference to figure 3, the operation decay ab that comprises reflection loss (reflection loss) can be expressed as following relation with respect to the decay a of cable:

a _B＝a+20log|q ₁|+20log|q ₂|+20log|w|

$q_1=\frac{Z_1+{\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="A20071012920100131.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0}{2\sqrt{Z_1{Z}_0}}$ ${\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="A20071012920100111.png,A20071012920100131.png"\; state="\{\{state\}\}">q</figure-callout>}}_2=\frac{{\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="A20071012920100131.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0+{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="A20071012920100111.png,A20071012920100131.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2}{2\sqrt{Z_0{Z}_2}}$ $w=1-\frac{Z_1-Z_0}{Z_1+{\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="A20071012920100131.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0}\&CenterDot;\frac{Z_2-Z_0}{{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="A20071012920100111.png,A20071012920100131.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2+{\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="A20071012920100131.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0}\&CenterDot;e^{-2\&CenterDot;\mathrm{\&gamma;}\&CenterDot;l}$

Wherein:

A is the decay that does not have the cable of reflection loss,

a _bBe the operation decay of cable,

q ₁And q ₂Be the loss that do not match that causes by the saltus step from the system impedance to the cable resistance,

W is the interaction loss that is caused by multipath reflection,

γ is the overall attenuation constant (complex attenuation constant) of cable,

L is the length of cable,

Z ₀Be the characteristic impedance of cable,

Z ₁Be the impedance of generator (generator), and

Z ₂It is the impedance of receiver.

For 100 ohm of system impedances and 130 ohm of cable resistance Z ₀Typical value, the loss q that do not match has only 0.1dB, compares it with the improvement of cable attenuation and can ignore.

For long cable length or high decay, this is the situation under the xDSL equipment, and interaction loss w trends towards 1, i.e. 0dB.

When adopting previous idea to attempt to optimize the cable of the bit rate that can keep higher, the applicant finds that the minimum value (minium measure) of PSACR value can advantageously be associated with the bit rate performance of cable 1.

PSACR is defined as the ratio (ACR) of decay and crosstalk.Adopt power and (power sum) (PS) to measure this ACR to obtain PSACR.In committee draft 46C/757/CD3.11 part, normative document IEC61156-1 1.2 versions and 3.0 versions, the PSACR measurement has been described.For claimed invention, every couple PSACR measures (dB) in the cable under the 1MHz frequency and at the cable length of 1km.For the purpose of this measurement, quad (quad) is considered to comprise two pairs.Though PSACR only is defined under the 1MHz, it is measured in the frequency range of 10MHz at 100KHz.Do like this that making to draw and measure the envelope of curves line and value from this envelope.This is very necessary, because PSACR, correspondingly the PSNEXT measured value depends on length and frequency, is presented to change the minimum and the maximum that will change when measuring length.

Lay length (twist lay length) is another parameter that influences performance.Lay length is the average measurement value in the coil buckling cycle of conductor 2 in the group 4.Stranded many more groups 4 mean that lay length is more little, cause performance better.But under a certain lay length value, the cost of coil buckling operation becomes very high.The present invention allows to obtain desired performance with 20mm or bigger constant lay length.

The group 4 of stranded conductor 2 can be the quad that comprises four conductors 2.It also can be to comprise that the line of two conductors 2 is right.

The diameter that another parameter relevant with performance is insulator 3 and the diameter ratio of insulated copper conductor 2.When the relative populations of insulator 3 increased, performance increased.It is too many that this performance is increased, because the overall diameter of cable and price also will increase in unacceptable mode.Conductor for quad adopts 1.8 such copper and insulator minimum ratios, and for line the conductor of marshalling is adopted 1.9 such copper and insulator minimum ratios, and the present invention allows the performance that obtains to expect.

Cable 1 can also be included in the group 4 of described conductor 2 and the shielding 7 between the described sheath 5.

At other embodiment that is intended to be used in the harsh application scenario of environment, cable 1 can also be included in the filler 6 that blocks water between described sheath 5 and conductor 2 described stranded group 4.

The material of the insulator 3 of conductor typically can be selected in following material: foam, foam-epidermis or epidermis-foam-epidermis polyolefin (for example polyethylene and polypropylene).The example of solid polyethylene is the product TR-210Alcudia  from Repsol.The poly example of foam-epidermis is the product HE1344 from Borealis.

The material of sheath 5 typically can be selected in following material: polyvinyl chloride (PVC), polyethylene (PE), have or do not have bonding laminated aluminium and the non-halogen compound of light cigarettes (low smoke zerohalogen compound) (LSZH), such as SCAPA S500 or POLYONE ECCOH5860.

Shielding 7 typically by metal for example aluminium (Al) band make, use out of doors.In this case, the typical thickness of metal tape is about 0.15-0.2mm.

For indoor use, shielding 7 is typically by metal and plastics, for example aluminium (Al) and polyester (PET), the interlayer band made of combination.In this case, the typical thickness of interlayer band is about 0.05mm.

In another embodiment, the xDSL cable can comprise the group 4 of a lot of quantity.In this case, some in these groups 4 can be combined bunchy.These bundles can be screened.Under the situation of line to many (for example 128 pairs), these line centerings some to or each quad in some composition bundles combine (for example 4 bundle 32 pairs).The line of these bundles is to making up in the mode of concentric layer (for example 5+11+16) or making up in the mode of child bundle (for example 4 bundle 8 pairs).These bundles or intrafascicular each of son can be screened or not screen.Fig. 7,8 shows the bunchy combination that corresponds respectively to 32 pairs of cables and 128 pairs of cables.

Each group 4 another embodiment that screen alone also is possible.

According to the present invention, the method that cable is determined can be undertaken by following steps: minimum PSACR is associated with the required bit rate of minimum.This minimum PSACR is known by the xDSL performance of testing in the actual copper cable foundation structure.Corresponding to this required minimum PSACR, select the minimum copper diameter and the minimum lay length of conductor 2.The PSACR performance of Huo Deing can guarantee the correlated performance of bit rate aspect like this.

In addition, the maximum of the ratio of the diameter of the diameter of copper conductor 2 and insulator 3 can be given before the step of determining maximum lay length is carried out.

Because the copper diameter is higher than lay length (increase of copper diameter causes insulation diameter to increase, promptly identical ratio, and final cable size increase) to the influence of cost, selects possible minimum copper diameter that minimum PSACR is provided.

The table of Figure 4 and 5 provides the illustrative examples according to cable of the present invention.They also provide the comparative descriptions with respect to the cable of prior art.

The form of Fig. 4 shows the right not filled cable of indoor volume.The cable of two prior aries is presented in first and second hurdles.Cable according to the present invention be presented at the 3rd and last hurdle in.

The form of Fig. 5 shows the filled cable of outdoor quad.The cable of three prior aries is presented at first in third column.Cable according to the present invention is presented in last hurdle.

Correspondingly, Fig. 6 shows the comparative characteristic curve of bit rate (is the vertical axis of unit with Mbit/s) with respect to cable length (is the trunnion axis of unit with km).Following curve is corresponding to cable of the prior art, and top curve is corresponding to improved cable according to the present invention.

Claims (13)

1, a kind of xDSL cable comprises a plurality of stranded group (4) that are inserted in copper conductor (2) in the sheath (5), that insulate respectively, it is characterized in that:

The diameter of copper conductor (2) be 0.4+/-0.05mm, the PSACR of cable (1) is more than or equal to 30dB, perhaps under 1MHz, when length is 1km

The diameter of copper conductor (2) be 0.5+/-0.05mm, under 1MHz, when length is 1km the PSACR of cable (1) more than or equal to 34dB,

Each stranded group (4) have the constant lay length more than or equal to 20mm.

2, xDSL cable according to claim 1, wherein said each group (4) be each line to or each quad.

3, xDSL cable according to claim 2, wherein for the conductor (2) of quad, the ratio of the diameter of the diameter of insulator (3) and copper conductor (2) is more than or equal to 1.8.

4, xDSL cable according to claim 2, wherein for the conductor (2) of paired marshalling, the ratio of the diameter of the diameter of insulator (3) and copper conductor (2) is more than or equal to 1.9.

5,, wherein also be included in the shielding (7) between described sheath (5) and described each group (4) conductor (2) according to each described xDSL cable in the claim 1 to 4.

6,, wherein also be included in the filler that blocks water (6) between described sheath (5) and described each group (4) conductor (2) according to each described xDSL cable in the claim 1 to 5.

7, according to each described xDSL cable in the claim 1 to 6, wherein said copper conductor (2) is used following insulated with material: foam, foam-epidermis or epidermis-foam-epidermis polyolefin.

8, according to each described xDSL cable in the claim 1 to 7, wherein sheath is made by following material: PVC, PE, the non-halogen compound of light cigarettes.

9, according to each described xDSL cable in the claim 1 to 8, wherein shielding (7) comprises the band of being made by following material: Al, Al+PET.

10,, combine and these bundles are screened according to each described xDSL cable in the claim 1 to 9 wherein some groups (4) bunchys.

11, according to each described xDSL cable in the claim 1 to 10, wherein each group (4) is screened separately.

12, the method for a kind of definite xDSL cable (1) is characterized in that, comprises the steps:

A) determine the minimum PSACR of minimum required bit rate and relevant cable;

B) minimum value of the diameter of selection copper conductor (2);

C) maximum of the constant twisting pitch of selection.

13, method according to claim 12 also comprises the step of minimum value of ratio of the diameter of the diameter of selecting insulator (3) and copper conductor (2).

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