JP2001143542A - Multi pair cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi pair cable that can satisfy both the power sum near end crosstalk attenuation standard of enhanced category 5 and the propagation delay time difference standard. SOLUTION: In a multi pair cable comprising an even number of units, which are formed with two pairs of twisted wires and an insulating layer is provided on around thereof, each pair of twisted wires being formed by twisting two wires, and being disposed on a circumference about the same center, and two types of units U1, U2 are alternately disposed, the pair of twisted wires for making units U1, U2 have a certain relation between a pitch of the twisted wires, and the specific permittivity of the insulating layer provided on around the units is below 4 at portions contacted with the pair of twisted wires and has a relation of t/r >=0.90, where t is the thickness of the insulating layer and r is the distance between wires of the pair of twisted wires.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-pair cable used for high-speed data signal transmission, and more particularly to a multi-unit type multi-pair cable formed by assembling a plurality of units each including a plurality of twisted pairs. .

[0002]

2. Description of the Related Art Twisted pair cables which are not shielded by twisting a plurality of pairs are mainly used as LAN cables which are used in a narrow area limited in a region, such as in an office or a commercial building. Used. This LAN cable is manufactured by the Electronic Industries Association of America / EIA / TIA
) And the International Organization for Standardization (ISO / IEC) determine and standardize specifications. In addition, a category 3 cable that can be used up to 10 MHz and a category 5 cable that can be used up to 100 MHz are specified.

[0003] Category 3 and category 5 cables are mainly composed of four twisted pair wires. These cables are mainly used for transmission systems such as 10BASE-T (Category 3 and Category 5 cables are used) and 100BASE-T (Category 5 cables are used.) One of the four twisted pairs is used for signal input. , And the other one is assigned to signal output, and the remaining two are reserved.

[0004] A main characteristic item required for the aforementioned LAN cable is a near-end crosstalk attenuation characteristic. And
In order to improve this characteristic, in the cables corresponding to the above-mentioned category 3 and category 5, the twist pitch lengths of the twisted pair wires constituting the cable are all different lengths, or the distance between the twisted pair wires is increased. A technique has been taken.

[0005]

At present, the International Standards Organization (ISO / IEC) has proposed an enhanced category 5 cable specification such as Gbi Ethernet which supports signal transmission at a speed higher than 100 MHz. This enhanced category 5 compatible cable is also mainly composed of four twisted pair wires. The near-end crosstalk attenuation characteristic of the enhanced category 5 is a stricter value than that of the conventional category 5. Also, in Gbit Ethernet, etc., unlike Category 3 and Category 5, there is a possibility that multiple or all twisted pair wires may be used for signal transmission and reception,
In the enhanced category 5, in addition to the near-end crosstalk attenuation characteristic, a regulation of the power sum near-end crosstalk attenuation characteristic is proposed. These standard values are shown in FIG.

Here, the power sum near-end crosstalk attenuation is
The integrated sum of the near-end crosstalk attenuation from one twisted pair in the cable to all other twisted pairs and is defined as: That is, in a cable having a logarithm n, all other twisted pair wires T _n (n: 2 to 2) with respect to the twisted pair wire T ₁ .
Power Sum Near End Crosstalk attenuation PNXT from n) is calculated by PNXT = 10log _{[10 ^ (NXT 2/10)} + 10 ^ (NXT 3/10) + ··· + 10 ^ (NXT n / 10)] You. Here, the twisted pair wire T ₁ and the twisted pair wire T _n
(N: 2-n) near-end crosstalk attenuation (unit)
dB) is NXT _n, and “＾” represents a power, for example, A ＾
B = and A ^B. Then, the power sum is calculated for all the n pairs of twisted pairs, and it is required that these values satisfy the standard values.

As described above, in order to improve the near-end crosstalk attenuation characteristic, there is a method of changing the twisted pitches of the twisted pair wires constituting the cable, for example. In order to satisfy the crosstalk attenuation characteristics, it is necessary to greatly increase the difference in the twist pitch between the cables corresponding to Category 3, Category 5, and the like. On the other hand, Gbit Ethernet etc.
It is possible to use several or all twisted pair wires for transmitting or receiving signals. At this time, if a signal of a certain twisted pair of the signals transmitted in a plurality of twisted pairs is delayed, there is a possibility that the signal may be lost or the transmission speed may be reduced. For this reason, it is desirable that signals can be received simultaneously, and it is desirable that the propagation speed and propagation delay time of the twisted pair wires constituting the cable be the same.

In the above-mentioned Enhanced Category 5 standard, a standard has been proposed for this propagation delay time. According to the standard, the difference between the maximum value and the minimum value of the propagation delay time of the twisted pair wire constituting the cable ( Propagation delay time difference)
Is less than 45ns / 100m. In addition, Anixta Corporation of the United States has its own standard, and according to the standard, the propagation delay time difference is 25 ns / 100 m or less.

[0009] The propagation delay time of a twisted pair wire mainly depends on the relative permittivity and the twist pitch of the insulator of the insulating wire constituting the twisted pair wire. Regarding the relationship between the twist pitch and the propagation delay time, for example, assuming that the relative permittivity of the insulator, the outer diameter of the insulation, and the outer diameter of the conductor are equal in two twisted pairs, the twisted pair having a shorter twist pitch has a smaller twisted pair. Since the conductor length is longer than that of a twisted pair wire having a long twisted pair pitch, the propagation delay time is increased. For this reason, in order to reduce the propagation delay time difference of a multi-pair cable composed of a plurality of twisted pair wires, it is desirable that the difference between the twisted pitches of the twisted pair wires be zero or as small as possible.

However, as described above, in order to improve the near-end crosstalk attenuation characteristic, it is desirable to increase the difference in the twist pitch of the twisted pair wires constituting the cable. Therefore, in order to obtain a cable corresponding to the enhanced category 5, it is necessary to select a twisted pair pitch in consideration of both the near-end crosstalk attenuation characteristic and the propagation delay time difference.

On the other hand, as described above, a LAN cable is mainly a four-pair cable, and usually one 4-pair cable is used for one device. However, in recent years, office automation and commercial buildings have become OA-oriented, and the number of devices to which LAN cables are connected has increased, and the number of cables has tended to increase accordingly. For this reason, securing a wiring space and increasing the number of wiring steps are problems. Therefore, a multi-pair cable composed of multiple units is required, with the 4-pair cable as one unit. However, when the number of units increases, the outer diameter of the cable increases, and considering that the flexibility decreases,
The number of units is desirably 4 to 6.

In the above-mentioned multi-unit type multi-pair cable, in order to satisfy the power sum near-end cross-talk attenuation required for the above-described enhanced category 5 compatible cable, near-end cross-talk attenuation not only within the unit but also between different units. The twist pitch of the twisted pair wire must be determined in consideration of the quantity characteristics. As described above, there is a standard for the propagation delay time difference in the enhanced category 5 cable, and it is necessary to consider this point. However, a multi-unit multi-pair cable that satisfies these standards has not yet been proposed.

An object of the present invention is to provide a power sum near-end crosstalk attenuation of a proposed enhanced category 5 standard in a multi-unit type multi-pair cable formed by assembling a plurality of units in which a plurality of twisted pairs are assembled. Standard and propagation delay time difference standard within unit (25 ns / 100 m or less)
It is an object of the present invention to provide a multi-pair cable capable of satisfying both.

[0014]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and twists two twisted pair wires obtained by twisting two identical insulated wires each having a conductor provided with an insulating layer. In addition, in a multi-unit type multi-pair cable in which an even number of 4-pair cable units each having an outer periphery provided with an insulating layer and their centers are located on the same circumference, two types of cable units U ₁ , U ₂ are alternately arranged, and the four twisted pair wires T of the cable unit U _m (m = 1, 2)
The twist pitches p _mn of _mn (n = 1 to 4) are all different, and the insulation outer diameter of the insulation wire is d, and p _m1 <p _m2 <p _m3 <p _m4 (m =
As 1,2), the formula [1-1] p _m2 /d≧1.4 × p _m1 /d-2.3 formula (1-2) p _m3 /d≧1.4 × p _m2 /d-2.3 formula [1-3] p _m4 /d≧1.4×p _m3 /d−2.3 Equation [2] p _m4 / d ≦ 10 ^23/92 × p _m1 / d, and the insulating layer provided on the outer periphery of the cable unit U _m has at least a pair The relative dielectric constant of a portion in contact with the stranded wire T _mn is smaller than 4, the thickness is t, and the distance between conductors of the stranded wire T _mn is r, and the following equation is satisfied: [3] t / r ≧ 0.90 Things.

The present invention has been obtained as a result of intensive and experimental studies. That is, as described above, it is proposed to set the twist pitch p _mn of the twisted pair wires T _mn of the multi-unit type multi-pair cable and the relative permittivity and the thickness of the insulating layer provided on the outer periphery of the unit U _m. The power sum near-end crosstalk attenuation standard of the enhanced category 5 standard and the propagation delay time difference standard within the unit (25 ns / 100 m or less) can be satisfied.

[0016]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described in detail with reference to (a) to (c). Many-to-cable 1, as shown in FIG. 1 (a), 4 pairs four cable units U ₁ and U ₂ are alternately center stranded collectively with densely arranged so as to be positioned on the same circumference 9 And a jacket layer 10 is provided on the collective twist 9.

The cable unit U _m (m = 1, 2) is
As shown in FIG. 1B, four twisted pair wires T _mn (m =
1, 2, and n = 1 to 4), and an insulating layer 6 is provided on a unit twist 5 obtained by collectively twisting.

As shown in FIG. 1C, the twisted pair wire T _mn is formed by twisting two insulated wires 4 having an outer diameter d in which the conductor 2 is provided with an insulating coating layer 3 at a twist pitch p _mn . Things.

The multi-pair cable 1 was experimentally examined for the following four evaluation items. These evaluation items are: 1) power sum near-end crosstalk attenuation between any paired twisted pair wire and the other three pairs of twisted pair wires 2) propagation time difference between paired twisted pair wires within the unit 3) unit 4) A power sum near-end crosstalk attenuation between any pair of twisted wires in the above and four pairs of twisted wires of the other unit. The attenuation characteristics are naturally required evaluation items for LAN cables, and the attenuation characteristics of enhanced category 5 cables that are currently proposed by the International Organization for Standardization (ISO / IEC) are also considered. There is a standard.

First, an arbitrary twisted pair wire in the unit
Power-sum near-end leakage between the cable and the other three pairs of twisted pairs
The relationship between talk attenuation and twisted pitch was experimentally determined (evaluation
Item 1). The insulated wire 4 used was made of soft copper wire with an outer diameter of 0.5 mm.
Conductor 2 coated with insulating coating layer 3 made of polyethylene
And an outer diameter of 0.96 mm. Connect this insulated wire 4 to 7
Twist at a twist pitch of up to 30 mm, twist pitch
Have four different twisted pair wires T_mnWas formed. this
Twist pitch p_mnPairs of twisted wires T_mnFour, twisted
And an insulating layer 6 of flame-retardant soft polyvinyl chloride
Alms, unit U_mWas formed. Note that the twist pitch
The small value was set to 7 mm because the twisted pair T_mnIs the twist pitch of
_mn, When the insulation outer diameter of the insulated wire 4 is d, stable twisting
To twist at the pitch, the formula [4] p_mnThis is because it is known from experience that /d≧7.3.

In order to satisfy the power sum near-end crosstalk attenuation standard of the enhanced category 5 cable, the near-end crosstalk attenuation between two pairs of twisted wires constituting the cable is determined by the power sum near-end crosstalk attenuation. For the standard value of
Experience has shown that it is only necessary to have a 10 dB margin. Therefore, in the combination of the pair of twisted wires on the induction side and the pair of twisted wires on the guided side, the near-end crosstalk attenuation is experimentally examined for the relationship between the twisted pair pitch having a margin of 10 dB with respect to the standard value shown in FIG. I asked.

Let Pi be the twist pitch of the twisted pair of wires on the induction side, and Pj be the twist pitch of the pair of twisted wires on the guided side, and experimentally examine the relationship between Pi and Pj that satisfies the above conditions for the near-end crosstalk attenuation. I asked. The result is shown in FIG. In FIG. 2, the horizontal axis represents the twist pitch P i / d of the twisted pair wire on the induction side, and the vertical axis represents the twist pitch Pj / d of the twisted pair wire on the guided side. In FIG.
Combinations regions pair twisting pitch Pi and the counter twist pitch Pj with 10dB margin against standard value of near-end crosstalk attenuation, the upper area A ₁ the straight line L _1, the straight line L ₂ of the lower region A
Distributed in _two . Here, the straight line L ₁ is, Pj / d = 1.4P
i /d-2.3, L ₂ is Pj / d = (1 / 1.4 ) · (Pi / d) +
(2.3 / 1.4). Note that, of course, the straight lines L ₁ and L ₂ are symmetric with respect to the straight line Pj / d = Pi / d. From the above, twist pitch p _mn twisted pair T _mn of the unit U _m is an insulating outer diameter of the insulated wire 4 as d, to satisfy the above equation [1-1] - [1-3], the unit U _m satisfies the standard of the evaluation item 1.

Next, the relationship between the propagation time difference and the twist pitch in the unit was experimentally determined (evaluation item 2). FIG. 3 shows the results of the experiment. In FIG. 3, the horizontal axis shows the twist pitch p / d of the twisted pair wire, and the vertical axis shows the propagation delay time τ. From FIG. 4, the relationship between the twist pitch p / d and the propagation delay time τ can be experimentally represented by the following equation [5] τ (ns / 100 m) = 590−92 log (p / d).

Incidentally, the propagation delay time difference in the unit is the difference between the maximum value and the minimum value of the propagation delay time of the twisted pair wire constituting the unit. From Equation [5], the maximum value of the propagation delay time in the unit is the propagation delay time in the shortest pitch twisted pair of the unit, and the minimum value of the propagation delay time is the propagation delay time in the longest pitch paired twisted pair. It is.

In this embodiment, the unit U_m Is four
Twisted pair T_mn(N = 1 to 4).
Stranded wire T_mnIs the twist pitch of_mnAnd p_m1<P_m2
<P _m3<P_m4When the relationship is the most twist pitch
Large twisted pair wire T_m4Propagation delay time τ_m4Is the smallest and the most
Twin twisted wire T with small twist pitch_m1Propagation delay time τ _m1
Is the largest and unit U_m Propagation delay time difference Δτ_m 
Is Δτ_m = Τ_m1−τ _m4It is represented by

The standard of the propagation delay time difference in the unit corresponding to the enhanced category 5 is 25 ns / 100 m or less, but the actual target is 23 ns / 100 m or less with a margin provided. That is, the goal was to satisfy Δτ _m = τ _m1 −τ _m4 ≦ 23. Accordingly, using Equation (5), relationship equations (2) ^{_{p m4 / d ≦ 10 23/92 ·}} p m1 / d is obtained.

From the above, the twisted pair wire T _mn in the unit U _m
The twist pitch p _mn of the unit U _m equations [1-1] - the Power Sum considering near-end crosstalk attenuation standards in [1-3], to satisfy the equation [2] in consideration of the propagation delay time difference standards simultaneously There is a need. Of the pair twisting pitch p _mn, pitch P _m1 of minimum pitch, becomes p _m1 /d≧7.3 from Equation (4), p _m4 maximum pitch, the formula [1-1] - [1-3] From equation [2], p _m4 /d≦18.3.

Next, any pair twisted and Power Sum Near End Crosstalk attenuation between the other four twisted pairs of units U ₂ (evaluation item 3), and twisted pair in the unit U ₁ The attenuation (evaluation item 4) was examined. Twisted pitch p _{mn of the} twisted pair wires T _mn of the units U ₁ and U ₂ (m:
1, 2, n: 1 to 4), as shown in FIG.
Pitch combinations are set so that the pitch ranges partially overlap, and the overlap is made as small as possible. That is, the twist pitch p ₂₁ / d to p _{24 of} the unit U ₂
/ D satisfies the formulas [1-1] to [1-3] and the formula [2], and is as large as possible to obtain 10.2, 12.1, 14.7, 1
8.3. The pitch p ₁₁ twisted pairs of the unit U ₁ /
d to p ₁₄ / d are expressed by formulas [1-1] to [1-3] and formula [2].
Satisfy the above and make it as small as possible, 7.30, 7.95, 8.
85, 10.1 However, assuming that p ₁₄ / d is 10.1, p ₁₄ / d is close to p ₂₁ / d (= 10.2), which may cause deterioration of the near-end crosstalk attenuation characteristic. Therefore, p ₁₄ /
d is, p ₂₁ / d~p so large as possible the difference between the ₂₄ / d, an intermediate value of p ₂₁ / d and p ₂₂ / d, and 10.85.

Based on the above, prototypes of the unit U ₁ and the unit U ₂ were produced. That is, for the unit U _1, the insulated wire having a 0.96mm by coating a polyethylene 0.5mm of annealed copper _{wire, p 11 /d=7.3, p 12 /d=7.95,p} 13
/D=8.85, p ₁₁ = 7.0 determined from p ₁₄ /d=10.85
, P ₁₂ = 7.6, p ₁₃ = 8.5, and p ₁₄ = 10.5, twisted pairs T ₁₁ , T ₁₂ ,
T _13, T ₁₄ and twisting, and prototype units subjected to insulation layer of a soft vinyl chloride having a thickness of 0.60mm on the outer periphery. Also, the unit U _2, an insulating wire was 0.96mm by coating a polyethylene 0.5mm of annealed copper wire, p ₂₁ / d = 1
_{0.2, p 22 /d=12.1,p 23 /d=14.7,p 24} / d = 18.
3 obtained _{from, p 21 = 9.8, p 22} = 11.7, p 23 = 14.2,
p ₂₄ = 17.6 become twisted twisted twisted pair at a pitch _{T 21, T 22, T 23} , T 24 and twisting, the insulating layer alms units of soft vinyl chloride having a thickness of 0.60mm on the outer periphery Was prototyped.

Next, the prototype units U ₁ and U ₂
It was measured for the attenuation of the twisted pairs constituting the, for unit U _1, twisted pair T _11, T _12, T ₁₃ is not able to satisfy the attenuation standard and satisfy the standard only T _14. Also, the unit U _2, twisted pair T ₂₁ is not able to satisfy the attenuation _{standard, T 22, T 23, T} 24 was found to satisfy the standard.

From the above, it is necessary to study the twisting pitch in consideration of the attenuation characteristics. The relationship between the attenuation in the twisted pair and the twisting pitch is, for example, the twisting of two twisted pairs. It is known that if the relative permittivity, insulation outer diameter, conductor outer diameter, etc. of insulators are all equal except for the pitch, the twist amount of the twisted pair wire having a short twist pitch is greater than that of the insulator. For this reason, in the above-mentioned trial production, the amount of attenuation can be reduced by lengthening the twist pitch of the twisted pair wires constituting the units U ₁ and U ₂ .

[0032] As described above, the unit U ₁ is
The attenuation can be reduced by increasing the twist pitch of the twisted pair wire. However, unit U
_For the twist pitches p ₂₁ , p ₂₂ , p ₂₃ , and p ₂₄ of the twisted pair wires T ₂₁ , T ₂₂ , T ₂₃ , and T ₂₄ that constitute No. ₂ , the upper limit satisfying the targets of the near-end crosstalk attenuation and the propagation delay time difference It is a twist pitch, and it is not possible to further increase the twist pitch of the twisted pair wire, and it is necessary to reduce the attenuation by a method other than increasing the twist pitch. As a method of reducing the attenuation by a method other than increasing the twist pitch, there is a method of reducing the relative dielectric constant around the twisted pair wire. Therefore, performed studies to reduce the amount of attenuation to reduce the dielectric constant of the surrounding twisted pairs for units U _2, the dielectric constant of the surrounding it and twisted pair to increase the twist pitch for unit U ₁ A study was made to reduce the amount of attenuation by lowering it.

The twisted pair wires T ₁₁ , T forming the unit U _1
In selecting the twist pitches p ₁₁ , p ₁₂ , p ₁₃ , and p ₁₄ of T ₁₂ , T ₁₃ , and T ₁₄ , select a twist pitch as long as possible from the problem of attenuation, and prevent deterioration of near-end crosstalk attenuation characteristics. T ₂₁ , T ₂₂ , T ₂₃ , T constituting the unit U _{2
Twenty-four} twist pitches p ₂₁ , p ₂₂ , p ₂₃ , and p ₂₄ need to be set so that the difference between the twist pitches is large in any combination.

Here, the unit U₁ Make up the twisted pair
Longest of the twist pitches₁₄Given the choice of
U_Two The longest of the twist pitches of twisted pair wires
p_{twenty four}Choosing a longer pitch will result in near-end crosstalk attenuation
Impossible due to limitations of characteristics and propagation delay difference
, P_{twenty four}You need to choose a shorter pitch. There
And p₁₄Is p_{twenty three}And p_{twenty four}Selected from the middle. in this way
If selected, p with close twist pitch_{twenty three}And p_{twenty four}Pi with
H difference is equal, p_{twenty three}Or p_{twenty four}Either of
Does not approach the value of_{twenty four}With a shorter pitch
That condition is also satisfied. From the above, p₁₄The value of / d is p
_{twenty three}/D=14.7, p_{twenty four}Since /d=18.3, 16.5 and
Become, p₁₃, P₁₂, P₁₁For p₁₄/ D value
Satisfies the equations [1-3], [1-2], and [1-1]
Select the maximum value₁₃/D=13.4, p ₁₂/ D = 11.15
 , P₁₁/D=9.60 was obtained.

[0035] Here, among the twisted pair T _mn, the (largest attenuation) smallest pair twist pitch in p ₁₁ / d to become twisted pair T _11, the attenuation characteristics (evaluation item 4)
To consider. As a means for reducing the amount of attenuation so as to be smaller than the standard value, there is a method of reducing the dielectric constant around the twisted pair wire (unit outer periphery). Therefore, the twisted pair T _11, were measured attenuation relationship between the dielectric constant of the unit U ₁ the outer circumference of the insulating layer 6. The result is shown in FIG. As can be seen from FIG. 5, when the value of the relative dielectric constant of the insulating layer 6 on the unit U ₁ periphery is 4 or less, attenuation level - serve as (standard value measurement) is more than 0 dB, the standard of the attenuation characteristics To be satisfied.

In order to increase the near-end crosstalk attenuation between the units U ₁ and U ₂ , there is a method of increasing the thickness of the insulating layer 6.
Therefore, the thickness of the insulating layer 6 on the outer periphery of the units U ₁ and U ₂ that can obtain a margin of 10 dB with respect to the standard value of the near-end crosstalk attenuation characteristic (the condition of the power sum near-end crosstalk attenuation standard) can be obtained. Study was carried out. The prototype sample has a 0.5 mm soft copper wire covered with high-density polyethylene and has an insulation outer diameter of 0.90 and 0.9 mm.
Four types of insulated wires 4 of 96, 1.10, and 1.20 were used. As described above, p ₁₁ / d to p ₁₄ / d are 9.6
, 11.15, 13.4, 16.5, and p ₂₁ / d to p ₂₄ / d are 1
0.2, 12.1, 14.7, and 18.3. Further, the unit U ₁
And the insulating layer 6 on the periphery of the unit U _2, the flame retardant polyethylene (dielectric constant of 3.2 (<4)) obtained by the extrusion coating, 0.05 thickness t of the insulating layer 6 in the range of 0.6 ～1.1Mm
Eleven types of insulating layers 6 were formed by changing the unit in mm. Therefore, 44 types of samples were produced by combining 4 types of insulating wires and 11 types of insulating layers.

With respect to a four-pair cable in which the above-mentioned four units U ₁ and unit U ₂ are alternately arranged densely and concentrically, between the adjacent units U ₁ and U _{2 and} between the opposing units U ₁ and U ₁ , And between units U ₂ and U ₂ , the near-end crosstalk attenuation was measured. The results are shown in FIGS. In FIG. 6-8, (a value obtained by subtracting the standard value from the measured values of the near-end crosstalk attenuation) on the vertical axis near-end crosstalk attenuation level, the thickness of the insulating layer 6 on the unit U _1, U ₂ outer peripheral horizontal axis The value t / r is obtained by dividing the length t by the distance r between conductors of the twisted pair wires (equal to the insulation outer diameter d). As can be seen from FIGS. 6 to 8, if t / r ≧ 0.90 (formula [3]), any combination between the two units U ₁ and U ₂ satisfies the target near-end crosstalk attenuation standard. On the other hand, a margin of 10 dB is obtained.

The distance between a plurality of units constituting the multi-pair cable does not change even if the total number of adjacent units increases, but the distance between non-adjacent units is four. It is the shortest for a cable that is a book. Therefore, the condition of equation [3] for a cable having four units can be applied even when the number of units is increased to six or eight.

(Embodiment) FIGS. 9A to 9C are cross-sectional views of one embodiment of a multi-pair cable according to the present invention, a cross-sectional view of a unit Um of the cable, and a twisted pair T of the cable. It is sectional drawing of _mn . The insulated wire 4 constituting the cable 1 is obtained by applying an insulating coating layer 3 made of high-density polyethylene to a conductor 2 made of a soft copper wire having an outer diameter of 0.5 mm, and having an outer diameter of 0.96 mm.

Unit U₁ Twists the insulated wire 4
T twisted wire T₁₁~ T₁₄And twist it around the circumference.
The thickness of the insulating layer 6 made of non-woven fabric with an electric power of 2.0 is 0.32 mm
And wrap it over the outer periphery of a 0.55mm thick
Covers insulation layer 7 made of polyvinyl chloride (relative dielectric constant 5.1)
It was done. Twisted wire T₁₁~ T₁₄Twist pitch p
₁₁~ P₁₄Are the same as Equations (1-1) to (1-3) and Equation (2).
Sometimes satisfied, 9.3mm, 10.7mm, 12.8mm, 15.7mm
It is. Unit U_Two Is the unit U₁ Similar to
Structured, twisted pair T_{twenty one}~ T _{twenty four}Twist pitch p
_{twenty one}~ P_{twenty four}Are the same as Equations (1-1) to (1-3) and Equation (2).
Sometimes satisfied, 9.8mm, 11.6mm, 14.1mm, 17.6mm
It is what it was.

The units U ₁ and U ₂ are twisted so as to be alternately arranged at the center via an interposition 11 made of a twisted string of polypropylene. Further, the outer periphery of the unit is twisted U ₁ and the unit U _2, the thickness
Presser winding 12 made of 0.025mm polyester tape
And a coating layer 13 made of polyvinyl chloride having a thickness of 0.85 mm is provided on the outer periphery thereof.

[0042] For the cable 1, between the unit U ₁ and the unit U _2, between the units U ₁ together was measured near end crosstalk attenuation of the twisted pair between the unit U ₂ together. The results are shown in FIGS. As can be seen from FIGS. 10 to 12, the near-end crosstalk attenuation of the twisted pair satisfies the target Category 5 standard + 10 dB margin in any combination of units.

[0043] Moreover, the cable 1 is composed of a twisted pair of 16 pairs, but each pair twisted constituting the unit U ₁ and the unit U _2, near-end crosstalk in combination with other 15 twisted pair The attenuation was measured, and the power sum near-end crosstalk attenuation was calculated from the measured value. The results are shown in FIGS.
It is shown in FIG. As can be seen from FIGS. 13 and 14, all of the twisted pairs of units U ₁ and the unit U ₂ satisfies a Power Sum Near End Crosstalk attenuation standard of Enhanced Category 5.

Further, the units U ₁ and U ₂
The propagation delay time difference between the four twisted pair wires
21ns / 100m, 20ns / 100m, target 25ns / 100m
Was satisfied.

[0045]

As described above, according to the present invention, the power sum near-end crosstalk attenuation standard and the propagation delay time difference standard (unit) in the enhanced category 5 standard proposed by the International Standards Organization (ISO / IEC) are provided. 25ns / 1
00m or less) can be obtained.

[Brief description of the drawings]

1A to 1C are a cross-sectional view of a multi-pair cable, a cross-sectional view of a unit of the multi-pair cable, and a cross-sectional view of a twisted pair of the multi-pair cable, respectively.

FIG. 2 is a diagram showing a range of a pair twist pitch in which a near-end crosstalk attenuation has a margin of 10 dB with respect to a standard value in a pair of twisted pairs.

FIG. 3 is a diagram showing a relationship between a twist pitch of a twisted pair wire and a propagation delay time.

FIG. 4 is a diagram showing a relationship between twisting pitches between units.

FIG. 5 is a diagram showing the relationship between the relative dielectric constant of an insulating layer outside the unit and the amount of attenuation (standard value-measured value).

FIG. 6 shows the thicknesses of the outer insulating layers of the units U ₁ and U ₂ ;
Near-end crosstalk attenuation between units U ₁ and the unit U ₂ - is a diagram showing the relationship between (standard value measurement).

The thickness of 7 insulating layer of the outer layer of the unit U _1, the near end crosstalk attenuation between the units U ₁ together - is a diagram showing the relationship between (standard value measurement).

The thickness of 8 insulating layer of the outer layer of the unit U _2, near-end crosstalk attenuation between the units U ₂ each other - is a diagram showing the relationship between (standard value measurement).

9A to 9C are a cross-sectional view of a multi-pair cable according to an embodiment of the present invention, a cross-sectional view of a unit of the multi-pair cable, and a cross-sectional view of a twisted pair of the multi-pair cable, respectively. It is.

FIG. 10 is a diagram showing a relationship between a near-end crosstalk attenuation amount and a frequency between the unit U ₁ and the unit U _{2 in the} embodiment.

11 is a diagram showing a relationship between the near end crosstalk attenuation and frequency between the unit U ₁ together in the above embodiment.

12 is a diagram showing a relationship between the near end crosstalk attenuation and frequency between the unit U ₂ together in the above embodiment.

13 is a diagram showing a relationship between the Power Sum Near End Crosstalk attenuation and the frequency of the twisted pairs of the unit U ₁ in the above embodiment.

14 is a diagram showing a relationship between the Power Sum Near End Crosstalk attenuation and the frequency of the twisted pairs of the unit U ₂ in the above embodiment.

FIG. 15 is a diagram showing a standard for a relationship between a near-end crosstalk attenuation and a frequency of an enhanced category 5 cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable 2 Conductor 3 Insulation coating layer 4 Insulation wire 5 Unit twist 6, 7 Insulation layer 9 Collective twist 10 Jacket layer 11 Interposition 12 Holding winding 13 Coating layer T Twisted wire U unit

Claims (1)

[Claims] 1. An even number of four-pair cable units comprising four pairs of twisted pairs formed by twisting two identical insulated wires formed by applying an insulating layer to a conductor, and applying an insulating layer to the outer periphery thereof. In a multi-unit type multi-pair cable whose center is located on the same circumference, two types of cable units U ₁ and U ₂ are alternately arranged, and the cable unit U _m (m = 1, 2) Four twisted pair wires T _mn (n = 1 to
The twist pitches p _{mn in} 4) are all different, and the insulation outer diameter of the insulated wire is d and p _m1 <p _m2 <p _m3 <p _m4 (m = 1, 2), and the equation [1-1] p _m2 / d ≧ 1.4 × p _m1 /d-2.3 formula [1-2] p _m3 /d≧1.4 × p _m2 /d-2.3 formula [1-3] p _m4 /d≧1.4 × p _m3 /d-2.3 formula [2 P _m4 / d ≦ 10 ^23/92 × p _m1 / d, and the insulating layer provided on the outer periphery of the cable unit U _m has a relative permittivity of at least a portion in contact with the twisted pair wire T _mn smaller than 4, A multi-pair cable characterized by the following formula: [3] t / r ≧ 0.90, where t is the thickness, and r is the distance between the conductors of the twisted pair wire T _mn .