JPH0955126A - Communication cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good transmission characteristic even in high-speed communication of 156Mbps by securing a margin decided by ISO/IEC-IS11801 regarding multiple cross talks so as to securing a multiple cross talks characteristic, dealing with the application of a different characteristic impedance by one communication cable and setting an ACR value at frequency 156MHz to be +10dB or higher. SOLUTION: A communication cable 10 is provided with a collecting twisting layer 12. The collection twisting layer 12 is formed by diagonally arranging two pairs of 14L1 and 14L2 having a characteristic impedance of 100Ω and two pairs of 14H1 and 14H2 having a characteristic impedance of 120Ω via an interposition 22. The outer diameters 16 of the insulated electric wires of these pairs 14L1 and 14L2 are equal and the outer diameters of the insulated electric wires of the pairs 14H1 and 14H2 are equal. But the outer diameters 16 of the insulated electric wires between the pairs 14L1 and 14L2 and the pairs 14H1 and 14H2 are different. Further, the twisting pitches of these pairs 14 are selected and set so as to satisfy a specified condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication cable used for high-speed data communication and the like, and more particularly, to an improvement of a communication cable having a collective twist layer formed by collectively twisting a plurality of pairs.

[0002]

2. Description of the Related Art As a communication cable used in a regionally limited area such as in an office or a building,
Generally, an indoor line or a premises cable that mainly transmits an audio signal, or an American Electronics and Information Technology Industries Association / American Telecommunications Industry Association (hereinafter,
It is called "EIA / TIA". ) A communication cable formed by twisting a plurality of pairs for data transmission up to 10 Mbps which is standardized by -568A is used. In these communication cables, conventionally, by twisting adjacent pairs with different twist pitches, or by setting the relationship between the twist pitches of each pair so as not to be an integral multiple,
The crosstalk characteristics were improved.

Further, in recent years, in the premises wiring system of offices and commercial buildings, the demand for high-speed data communication of about 100 Mbps is increasing,
Recently, 100M formed by twisting multiple pairs
Communication cables that can be used for data transmission up to bps are used for future multimedia applications. Regarding the communication cable that can be used for data transmission up to 100 Mbps, the standard is similarly defined in EIA / TIA-568A.

These communication cables have been standardized mainly in the United States, and based on this standard, the International Organization for Standardization / International Electrotechnical Commission (hereinafter referred to as "ISO / IEC").
Say. ) Is promoting international standardization. In this standard, single mode or multimode optical fiber, 100Ω balanced, 1
A 20 Ω balanced, 150 Ω balanced quad or a twisted pair of cables is specified.

Regarding these balanced cables,
Balanced cables with a single characteristic impedance corresponding to the equipment for each characteristic impedance have been used.
For example, the current computer network (hereinafter "LA
N ”. ) For one terminal, one pair at the input, one pair at the output, assigning a total of two pairs to the input and output, while including two spare pairs to accommodate future new applications, Although the total of four pairs is formed, the characteristic impedances of these four pairs all have the same characteristic impedance.

[0006]

However, a communication cable having a single characteristic impedance cannot support applications for LANs having different characteristic impedances. Moreover, one communication cable is, for example, 10
When used simultaneously in two applications with different characteristic impedances of 0Ω and 120Ω, there are two pairs on the transmitting side (induction side) and two pairs on the receiving side (induced side), so they were transmitted simultaneously. In consideration of multiple crosstalk from signals, it is necessary to sufficiently reduce the near-end crosstalk attenuation not only between pairs having the same characteristic impedance but also between pairs having different characteristic impedances.
Especially, regarding this multiple crosstalk, ISO / IEC-IS
By 11801, with respect to the standard value of the near-end crosstalk attenuation amount defined in Category 5 of EIA / TIA-568A,
Standard value + [6 + 10 log (n + 1): n represents the number of units (combination of pairs) adjacent to a certain unit (combination of pairs). ] Since there is a stricter requirement that a margin of about dB be provided, it is necessary to give consideration so that it can be cleared.

In the future, for example, an asynchronous transfer mode computer network (hereinafter referred to as "ATM LA"
N ”), high-speed data communication of about 156 Mbps is required, and the demand for high-speed data communication of 100 Mbps or more increases. Therefore, this 100Mb
15 ps or more, especially required in ATM LAN
For a communication cable that can be used for high-speed data communication of about 6 Mbps, it is necessary to improve frequency characteristics such as attenuation and near-end crosstalk attenuation.

Here, when considering the transmission characteristics of the communication cable, the ACR value which is a value obtained by subtracting the measured value (dB) of the attenuation amount from the measured value (dB) of the near-end crosstalk attenuation amount is important. It will be an index. That is, when transmitting a digital signal, the bit error rate, which is the rate of occurrence of data errors such as 0 being transmitted to 1 and vice versa, becomes a problem.
The bit error rate of 10 ⁻¹⁰ (error occurrence rate of once in ¹⁰ billion times) is an index for enabling good data transmission, which corresponds to an ACR value of +10 dB. Therefore, the E related to the communication cable that can be used for the current high-speed data communication up to 100 Mbps.
A communication cable capable of clearing the standard of Category 5 of IA / TIA-568A can simultaneously secure +10 dB as the ACR value at 100 MHz in the communication cable 100 m.

In this EIA / TIA-568A, 10
Since the ACR value related to high-speed data communication exceeding 0 Mbps is not shown, it is necessary to examine how much ACR value should be secured at 156 Mbps to obtain good transmission characteristics. In this case, E
In IA / TIA-568A, regarding high-speed data communication of 100 Mbps, the frequency up to 100 MHz is the upper limit of the standard, and the ACR value at the time of transmitting 100 Mbit data at the maximum 100 MHz is +10 dB. Therefore, for high-speed data communication of 156 Mbps, if +10 dB is similarly secured as the ACR value at the maximum of 156 MHz, data transmission in almost any necessary frequency band including data transmission at frequencies lower than that is good. It is considered that various transmission characteristics can be obtained. In particular, ATM L
In AN, in practice, 1 at a frequency of about 50-78 MHz.
Since data transmission of 56 Mbps is performed, it is considered that good transmission characteristics can be surely secured even in this practical level frequency band.

In view of the above points, an object of the present invention is to improve near-end crosstalk attenuation not only between pairs having the same characteristic impedance but also between pairs having different characteristic impedances, so that ISO / IEC can be applied to multiple crosstalk. -IS1
A single communication cable can be applied to applications with different characteristic impedances while securing a good multiple crosstalk characteristic and a sufficient amount of attenuation by securing the margin defined by 1801.
ACR value in Hz is +10 dB or more, 100M
It is an object of the present invention to provide a communication cable capable of obtaining excellent transmission characteristics even in high-speed data communication of bps or more, especially 156 Mbps.

[0011]

According to the present invention, as a first means for solving the above problems, a plurality of pairs formed by twisting two cores of insulated electric wires are twisted so that adjacent pairs have different twist pitches. In a communication cable having a collective twisted layer formed by collective twisting, the plurality of pairs are made up of at least two pairs having different characteristic impedances, with two pairs having the same characteristic impedance as one pair. , A plurality of pairs provide a communication cable characterized in that the one pair of two pairs are diagonally arranged and twisted together.

As a second means for solving the problem, the present invention is the above-mentioned means for solving the first problem, wherein, of the two pairs having different characteristic impedances, two pairs having a lower characteristic impedance, T _L1. , T _L2 twist pitch P _L1 , P _L2
And two pairs of higher characteristic impedance T _H1 ,
It is intended to provide a communication cable characterized in that the twist pitches P _H1 and P _{H2 of} T _H2 are each selected from a region that simultaneously satisfies the following conditions (1) to (3). Condition (1) The twist pitches P _L1 and P _L2 of the pair of low characteristic impedance T _L1 and T _L2 are selected from the range of P _L1 × P _L2 ≦ 150, and when P _L1 <P _L2 , P _L1 / P _L2 ≦ 0.85 (Mathematical formula) When P _L1 > P _L2 , P _L1 / P _L2 ≧ 1.18 (Mathematical formula) Condition (2) High characteristic impedance pair T _H1 , T _H2 twist pitch P _H1 and P _H2 are selected from the range of P _H1 × P _H2 > 150, and when P _H1 <P _H2 , when P _H1 / P _H2 ≦ 0.8 (formula) P _H1 > P _H2 Is P _H1 / P _H2 ≧ 1.25 (Equation) Condition (3) Low characteristic impedance pair T _L1 , T _L2 twist pitch P _L1 , P _L2 maximum value P _{L (Max)} and high characteristic impedance The minimum value P _{H (Min)} of the twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 satisfies the following relationship. P _{L (Max)} / P _{H (Min)} ≦ 0.8 (mathematical formula)

As a third problem solving means, the present invention is the above first problem solving means, wherein, of the two pairs having different characteristic impedances, the two pairs T having a lower characteristic impedance are used. _L1, twist pitch of T _L2 P _L1, P
_L2 and the twist pitches P _H1 and P _{H2 of the} two pairs T _H1 and T _H2 of the pair having the higher characteristic impedance are selected from the regions that simultaneously satisfy the following conditions (4) to (6), respectively. The present invention provides a communication cable characterized by the above. Condition (4) The twist pitches P _L1 and P _L2 of the pair T _L1 and T _L2 of low characteristic impedance are selected from the range of P _L1 × P _L2 > 150, and when P _L1 <P _L2 , P _L1 / P _L2 ≤ 0.8 (Equation ′) When P _L1 > P _L2 , P _L1 / P _L2 ≧ 1.25 (Equation ′) Condition (5) High characteristic impedance pair T _H1 , T _H2 twist The pitches P _H1 and P _H2 are selected from the range of P _H1 × P _H2 ≦ 150, and when P _H1 <P _H2 , P _H1 / P _H2 ≦ 0.85 (equation ') P _H1 > P _{When H2} , P _H1 / P _H2 ≧ 1.18 (Equation ') Condition (6) The minimum value P _{L (Min)} of the twist pitches P _L1 and P _L2 of the pair of low characteristic impedance T _L1 and T _L2 , The maximum value P _{H (Max)} of the twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 of high characteristic impedance satisfies the following relationship. P _{L (Min)} / P _{H (Max)} ≧ 1.25 (Formula ')

Furthermore, the present invention provides, as a fourth means for solving the above problems, in any one of the means for solving the above problems, one pair of two pairs having the same characteristic impedance is provided outside the insulated wire of two cores. A plurality of pairs having the same diameter and different characteristic impedances provide a communication cable in which the insulated wires forming the pairs have different outer diameters.

Thus, for example, in a telecommunication cable having a collective twisted layer consisting of four pairs, one pair of two pairs having a characteristic impedance of 100Ω and also 12 pairs.
If two pairs having a characteristic impedance of 0Ω are set as one set and these pairs are combined and two pairs of two types having different characteristic impedances are diagonally arranged and twisted, two pairs having different characteristic impedances are twisted. Since they serve as spacers, and a distance can be provided between pairs having the same characteristic impedance, a single communication cable can be used for applications with different characteristic impedances while ensuring good near-end crosstalk characteristics. Therefore, the communication cable can be effectively used.

In this case, in particular, when the twist pitches of a plurality of pairs are numerically limited as described above, the twist pitches of adjacent pairs are always different, and as shown in the experimental examples and examples of the present invention described later. , Since each pair is twisted at the optimum twist pitch obtained as a result of the experiment, the near-end crosstalk attenuation is improved not only between pairs with the same characteristic impedance but also between pairs with different characteristic impedance. Since I can
The margin defined by SO / IEC-IS11801 can be secured, and one communication cable can be used for two applications with different characteristic impedances while securing good multiple crosstalk characteristics and attenuation.

Further, as shown in an experimental example and an embodiment of the present invention described later, the characteristics of the near-end crosstalk attenuation amount and the attenuation amount are improved, and at the same time, 15
The ACR value at 6 MHz can be set to +10 dB or more, and 100 Mbps or more, particularly 156 Mbps.
Good transmission characteristics can be obtained even in high-speed data communication.

Furthermore, in these cases, when the insulated wires forming the pair are made to have different outer diameters, when the holding winding or the shield layer is provided on the gathered twisted layer, the occupation ratio of the air around the pair is increased. Since it becomes large, by decreasing the dielectric constant, the amount of attenuation can be reduced, and better transmission characteristics can be obtained. In particular, the ACR value, which is the value obtained by subtracting the amount of attenuation from the near-end crosstalk attenuation, It is effective in improving.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a communication cable 1 of the present invention.
0, and in the embodiment shown in FIG.
Reference numeral 0 includes the collective twist layer 12 and the shield layer 24 applied to the collective twist layer 12.

As shown in FIG. 1, the shield layer 24 is a polyester tape 2 having aluminum adhered on both sides.
It can be formed by wrapping 6 or the like. In order to reduce the amount of attenuation, the shield layer 24, as shown in FIG.
It is provided on top of 2.

Further, in the embodiment shown in FIG. 1, a braid 30 is further provided on the shield layer 24 so that reception of a desired electromagnetic signal is impaired by an unnecessary electromagnetic signal or electromagnetic disturbance. (Hereinafter referred to as "EMI") is prevented. Note that this EMI characteristic may be improved by applying another shield layer 24, for example, a metal pipe. Further, as shown in FIG. 1, a sheath 32 is provided on the braid 30 to protect the assembled twisted layer 12 and the shield layer 24 from the external environment. The sheath 32 can be formed of, for example, polyvinyl chloride or polyethylene.

As shown in FIG. 1, the collective twist layer 12 is formed by collectively twisting a plurality of pairs 14. In the present invention, the plurality of pairs 14 are composed of at least two pairs 14 having different characteristic impedances, with two pairs 14 having the same characteristic impedance as one pair. In the embodiment shown in FIG. 1, ISO / IEC-I is used.
Two pairs 14 having characteristic impedances of 100Ω and 120Ω specified in S11801 were used. Specifically, as shown in FIG.
Two pairs 14L ₁ , with characteristic impedance of Ω, 1
The 4L ₂ group and the two pairs 14H ₁ and 14H ₂ having a characteristic impedance of 120Ω are composed of 4 pairs 14 in total.

Therefore, one communication cable 10 can be used for a plurality of applications having different characteristic impedances. For example, the pair 14L ₁ and 14L ₂ are used for a LAN device having a characteristic impedance of 100Ω.
Characteristic impedance of pair 14H ₁ and 14H ₂ is 120Ω
It is possible to simultaneously use the LAN equipment for simultaneous data transmission. It should be noted that the number of pairs 14 is not necessarily limited to these four, and if necessary, for example, a pair of two pairs 14 having a characteristic impedance of 150Ω may be added to make a total of six. It is also possible to use other suitable numbers such as a pair 14 and corresponding to three different applications. In the illustrated embodiment,
Although the combination of 100Ω and 120Ω is selected as the different characteristic impedance, it is needless to say that another combination of different characteristic impedances such as 100Ω and 150Ω or 120Ω and 150Ω may be selected as necessary. .

Each pair 14 is, as shown in FIGS. 1 and 2,
It is formed by twisting two-core insulated electric wires 16. Each of the insulated wires 16 is formed by covering a conductor 18 with an insulating layer 20, as shown in FIG. This conductor 18
For example, annealed copper wire or the like can be used, and the insulating layer 20 can be formed of, for example, polyethylene, polypropylene, or the like. In particular, when the insulating layer 20 is formed of expanded polyethylene or expanded polypropylene, it has a low dielectric constant. It is possible because it is possible.

Further, 1 having the same characteristic impedance
Two pairs 14 of a set, namely pair 14L₁ And 14L
₂ , Again 14H₁ And pair 14H₂ Constitute pair 14
The outer diameters of the two-core insulated wire 16 are equal,
Two pairs 14 with different pedances, namely pair 14L₁ 
And pair 14L₂ And 14H₁ And pair 14H₂ And is
The insulated wires 16 of 14 have different outer diameters. Specifically, 10
One pair 14L with low characteristic impedance of 0Ω
₁ The outer diameter of the insulated wire 16 of_L1And the other pair 14L₂ of
The outer diameter of the insulated wire 16 is d_L2And similarly, high 120Ω
One pair 14H having a high characteristic impedance₁ Insulation
The outer diameter of the wire 16 is d_H1And the other pair 14H ₂ Insulated wire
16 outer diameter d_H2Then, as shown in FIG. 1, d_L1=
d_L2(= D_L ) And again d_H1= D_H2(= D_H ) Becomes
But d_L = D_H Does not hold and d_L ≠ d_H (Shown in Figure 1
Sea urchin d_L <D_H Or d_L > D_H ).

As described above, the insulated wire 1 forming the pair 14
When the outer diameters of 6 are made different, as shown in FIG. 1, when the press winding 28 and the shield layer 24 are provided on the gathered twisted layer 12, the occupancy ratio of the air around the pair 14 becomes large.
By reducing the dielectric constant, the amount of attenuation can be reduced. This is particularly effective in improving the ACR value, which is the value obtained by subtracting the attenuation amount from the near-end crosstalk attenuation amount described below.

The outer diameter of the insulated wire 16 can be determined by adjusting the foaming rate. Further, in this case, the pair 14 having a larger outer diameter of the insulated wire 16 is more likely to be crushed because the insulating layer 20 has a higher foaming rate, and the crushing of the insulating layer 20 is larger as the twist pitch value of the pair 14 is smaller. Therefore, it is preferable to lengthen the twist pitch of the pair 14 in which the insulated wire 16 has a large outer diameter.

Also, these four pairs 14L ₁ and 14L
₂ , 14H ₁ and 14H ₂ are twisted so that adjacent pairs 14 have different twist pitches so that crosstalk does not occur. Thus, for example, the adjacent pairs 14 shown in FIG.
The twist pitch P _{L1 of one} pair 14L ₁ of L ₁ and pair 14H ₁
And the other pair 14H ₁ has a different twist pitch P _H1 , which means that pair 14H ₁ and pair 14L ₂ and pair 14L ₂ and pair 14H 1
₂ and also between the pair 14H ₂ and the pair 14L ₁ .
That is, when the twist pitch of the pair 14L ₁ is P _L1 , the twist pitch of the pair 14H ₁ is P _H1 , the twist pitch of the pair 14L ₂ is P _L2 , and the twist pitch of the pair 14H ₂ is P _H2 , P _L1 ≠ P _H1 ,
P _H1 ≠ P _L2 , P _L2 ≠ P _H2 , and P _H2 ≠ P _L1 always hold.
It should be noted that the twist pitch of the pair 14 is 2 that constitutes each pair 14.
The pitch at which two insulated wires 16 are twisted together.

The plurality of pairs 14 are further twisted with a pair of two pairs 14 having the same characteristic impedance arranged diagonally. Specifically, in the case of four pairs 14, as shown in FIG.
The two pairs 14L ₁ and 14L ₂ are diagonally arranged, and the two pairs 14H ₁ and 14H ₂ having the higher characteristic impedance are diagonally arranged. Therefore, as shown in FIG. 1, in the case of four pairs 14, pair 1 having different characteristic impedances is used.
Pairs 4 are arranged alternately and have different characteristic impedances
4 are spacers to each other and between pairs 14 having the same characteristic impedance, that is, pair 14L ₁ and pair 14L
_Since it is possible to provide a distance between the pair 14 and the pair 14H ₁ and the pair 14H ₂ , it is possible to maintain a good near-end crosstalk characteristic particularly with respect to the combination of the pair 14 having the same characteristic impedance. The communication cable 10 can support applications with different characteristic impedances, and the communication cable 10 can be effectively used.

In this case, these four pairs 14L ₁ , 1
4L ₂ , 14H ₁ and 14H ₂ prevent the pair 14 from falling down to the center and causing the collapse of the twist of the collective twisted layer 12, so that as shown in FIG. It is desirable to set twist around. As a result, the arrangement of the pairs 14 becomes stable and the distance between the diagonally arranged pairs 14 becomes long, so that the near-end crosstalk characteristic can be stabilized. In addition, as the interposition 22,
A string made of a thermoplastic resin can be used.

In the present invention, as shown in FIG.
When the collective twist layer 12 is formed from two pairs 14, the twist pitches P _L1 and P _L of the two pairs T _L1 and T _L2 of the pair having the lower characteristic impedance of the two pairs 14 having different characteristic impedances. A region where _L2 and the twist pitches P _H1 and P _{H2 of the} two pairs T _H1 and T _H2 of the pair having the higher characteristic impedance simultaneously satisfy the following conditions (1) to (3), or It is selected from any of the regions that simultaneously satisfy the following conditions (4) to (6).

Condition (1) The twist pitches P _L1 and P _L2 of the pair T _L1 and T _L2 of low characteristic impedance are P _L1 × P _L2 ≦ 1
When selected from the range of 50 and when P _L1 <P _L2 , P _L1 / P _L2 ≦ 0.85 (mathematical formula) When P _L1 > P _L2 , P _L1 / P _L2 ≧ 1.18 ( (2) Condition (2) The twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 of high characteristic impedance are selected from the range of P _H1 × P _H2 > 150, and when P _H1 <P _H2 , P _H1 / P _H2 ≦ 0.8 (Mathematical formula) When P _H1 > P _H2 , P _H1 / P _H2 ≧ 1.25 (Mathematical formula) Condition (3) Twisting of low characteristic impedance pair T _L1 and T _L2 The maximum value P _{L (Max) of the} pitches P _L1 and P _L2 and the minimum value P _{H (Min)} of the twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 having high characteristic impedance satisfy the following relationship. . P _{L (Max)} / P _{H (Min)} ≦ 0.8 (mathematical formula)

[0033] Condition (4) the pitch P _L1, P _L2 twisted pair of lower characteristic impedance T _L1, T _L2 is, P _L1 × P _L2> 1
When selected from the range of 50 and when P _L1 <P _L2 , P _L1 / P _L2 ≦ 0.8 (Equation ′) When P _L1 > P _L2 , P _L1 / P _L2 ≧ 1.25 (Formula ') Condition (5) The twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 of high characteristic impedance are selected from the range of P _H1 × P _H2 ≦ 150, and P _H1 <P _H2 When P _H1 / P _H2 ≦ 0.85 (Formula ') When P _H1 > P _H2 , P _H1 / P _H2 ≧ 1.18 (Formula') Condition (6) Pair of low characteristic impedance T _L1 , The minimum value P _{L (Min)} of the twist pitch P _L1 and P _L2 of T _L2 and the maximum value P _{H (Max)} of the twist pitch P _H1 and P _H2 of the pair T _H1 and T _H2 of high characteristic impedance are as follows. Satisfy the relationship. P _{L (Min)} / P _{H (Max)} ≧ 1.25 (Formula ')

When the twist pitches of a plurality of pairs 14 are set by limiting the numerical values in this way, each pair 14 has an optimum value obtained as a result of the experiment, as can be seen from the experimental examples and the examples of the present invention described later. Since they are twisted at a twist pitch, it is possible to improve near-end crosstalk attenuation not only between pairs 14 having the same characteristic impedance but also between pairs 14 having different characteristic impedances. It is possible to secure a margin defined by IS11801, and it is possible to cope with two applications of different characteristic impedances with one communication cable 10 while securing good multiple crosstalk characteristics and attenuation.

Further, as shown in the experimental example and the embodiment of the present invention described later, the characteristics of the near-end crosstalk attenuation amount and the attenuation amount are improved, and at the same time, 15
The ACR value at 6 MHz can be set to +10 dB or more, and 100 Mbps or more, particularly 156 Mbps.
Good transmission characteristics can be obtained even in high-speed data communication.

Further, in the communication cable 10 of the present invention, in order to satisfy these mathematical expressions, the plurality of pairs 14 are all twisted with different twist pitches, and as a result, the twist pitches of the adjacent pairs 14 are also different from each other. It will be.

The above-mentioned conditions (1) to (6)
And the pair 14L ₁ , 14 having a low characteristic impedance
L ₂ and pair 14H ₁ having high characteristic impedance, 1
With 4H ₂ , the twist pitch selection area is divided at the boundary of the product value of the twist pitch of the pair 14 of 150. In this case, the combination of the conditions (1) to (3) described above, The combination of the conditions (4) to (6) is the product of the twist pitches, and the pair of low characteristic impedances 14
L is set to "≤150" and the pair 14H having a high characteristic impedance is set to ">150", or conversely, the pair 14L having a low characteristic impedance is set to ">150" and a pair having a high characteristic impedance is set. The relationship regarding the twist pitch of the pair 14 is substantially the same, except that 14H is set to “≦ 150”.

Therefore, regarding the above equation, that is, the relationship between the twist pitches of the plurality of pairs 14, for example, the condition (1)
With reference to FIG. 1, the condition (3) will be described as an example. The communication cable 10 according to the embodiment shown in FIG.
The characteristic impedance of 4L ₁ and 14L ₂ is 100Ω,
Characteristic impedance of pair 14H ₁ and 14H ₂ is 120Ω
Therefore, the pair 14L ₁ and 14L ₂ become the pair 14 having a low characteristic impedance, while the pair 14H ₁ and 14H ₂ become the pair 14 having a high characteristic impedance. Therefore, one to one
The twist pitches P _L1 and P _L2 of 4L ₁ and 14L ₂ are selected from the range of P _L1 × P _L2 ≦ 150 according to the condition (1), and the twist pitches P _H1 and P _H2 of the pair 14H ₁ and 14H ₂ are According to the condition (2), P _H1 × P _H2 > 150 is selected.

Then, first, the combination of the pair 14 having the same characteristic impedance (specifically, the combination of the pair 14L ₁ and 14L ₂ shown in FIG. 1 and the pair 14H) is used.
For the relationship of the twist pitch of pair 14 in the combination of ₁ and pair 14H ₂ , the characteristic impedance of pair 1 is 1
4L ₁ twist pitch P _L1 and 14L ₂ twist pitch P L
_{With respect} to _L2 , when the twist pitch P _L2 is set to be larger (that is, P _L1 <P _L2 ), P _L1 / P _L2 ≦ 0.85 according to the formula of the condition (1) Select the twist pitch, while the high characteristic impedance pair 14H ₁
The twist pitch P _H1 of, in a pair 14H ₂ twist pitch P _H2, if you set larger at the pitch P _H2 twist _{(i.e., P H1 <P H2),} P from Equation condition (2) _H1 /
The twist pitch of pair 14 is selected so that P _H2 ≦ 0.8. As a result, the near-end crosstalk attenuation amount in the combination of the pair 14 having the same characteristic impedance is improved, and +10 dB or more can be secured as the ACR value at the frequency of 156 MHz.

Next, a combination of pairs 14 having different characteristic impedances (specifically, pair 14L ₂ and pair 14
Explaining the relationship of the twist pitch of the pair 14 in a total of 4 combinations of H ₁ etc.), in this case, since P _L1 <P _{L2 as} described above, P _{L (Max)} = P _L2 , while Since P _H1 <P _H2 , P _{H (Min)} = P _H1 and P _L2 / P _H2 ≦ 0 according to the condition (3), P _{L (Max)} / P _{H (Min)} ≦ 0.8. The twist pitch of pair 14 is selected to be 0.8. Thereby, the near-end crosstalk attenuation amount in the combination of the pair 14 having different characteristic impedances can be improved, and the multiple crosstalk characteristics are improved.

The communication cable 10 of the present invention is shown in FIG.
As shown in FIG. 4, it can be used as it is as one unit 42 of the so-called unit type communication cable 40. That is, each unit 42 has four pairs 1 in which a twist pitch of pairs 14 is selected from the above-mentioned area.
It is formed of a collective twist layer 12 formed by collectively twisting 4, a press winding 28 applied to the collective twist layer 12, and a shield layer 24 applied on the press winding 28. As shown in FIG. 3, the communication cable 40 of this unit type is obtained by collectively twisting these six units 42A to 42F through an interposer 44 provided as necessary,
The presser winding 46 is further covered on the presser winding 4
6 is covered with a sheath 48. In this case, in FIG. 3, the communication cable 40 includes six units 4
It is composed of 2A to 42F, but may be any other suitable number as required.

[0042]

EXAMPLES Next, the above-mentioned conditions (1) to (6) and the process of deriving mathematical expressions under these conditions will be described with reference to experimental examples, and the effects of the present invention will be described with reference to examples. Prove.

First, in the communication cable 10 in which four pairs 14 having a characteristic impedance of 100Ω formed by twisting two insulated wires 16 having an outer diameter of 0.94 mm are collectively twisted, these four pairs 14 are Fifteen experimental examples were set by changing the combination of twist pitches. Specific values of the twist pitch of the pair 14 in each experimental example are shown in Table 1 below.
As shown in.

[0044]

[Table 1]

For each of the experimental examples shown in Table 1, the near-end crosstalk attenuation amount was measured for all combinations of four pairs 14 (total of 6 combinations of pairs 14 for one experimental example).

In the experiment, the near-end crosstalk attenuation amount was examined using the pair 14 having the characteristic impedance of 100Ω and 120Ω shown in the embodiment of FIG. 1 as an example. In this case, the near-end crosstalk attenuation amount empirically depends on the twist pitch value of the pair 14 rather than the characteristic impedance value. For example, the pair 14 having the characteristic impedance of 100Ω and the characteristic impedance of 120Ω. 1 to
4, pair 1 with a characteristic impedance of 150Ω
It is known that the relationship between the twist pitch value of the pair 14 and the near-end crosstalk attenuation amount is almost the same regardless of which of the four. Therefore, the near-end crosstalk attenuation amount obtained for the experimental example shown in Table 1 is actually obtained for the pair 14 having a characteristic impedance of 100Ω. However, this is as it is, the characteristic impedance of 120Ω or 150Ω. There is no problem even if it is considered by replacing it with the near-end crosstalk attenuation amount obtained for the pair 14 having. Therefore, in the evaluation of the experimental results described below, in examining the relationship between the twist pitch value and the near-end crosstalk attenuation amount for the pair 14 having the characteristic impedance of 120Ω, the pair 14 having the characteristic impedance of 100Ω was also examined. Got Pair 14
The relationship between the twist pitch value and the near-end crosstalk attenuation was applied as it was. Further, from this, it can be considered that the evaluation of the results of the experiment described below is also valid for the pair 14 having the characteristic impedance of 150Ω. Therefore, the present invention has been described in the above-described embodiment. Thus, as a composite of pairs 14 having different characteristic impedances, in addition to 100Ω and 120Ω, 100
It was considered that there was no problem even with a composite of Ω and 150Ω.

Next, the relationship between the combinations of the twist pitches of the pair 14 and the near-end crosstalk attenuation amount in each combination was investigated.

In this case, the ratio of the twist pitch of the pair 14 is adopted as an index for quantifying the combination of the twist pitch of the pair 14, and the relationship between the ratio of the twist pitch of the pair 14 and the near-end crosstalk attenuation amount is shown. Examined. This is because near-end crosstalk is generally considered to be dominated by the twist pitch ratio of pair 14.

[0049]

[Table 2]

The index indicating the near-end crosstalk level of each pair 14 is determined as follows. That is, as shown in Table 2, all combinations of pairs 14 in each experimental example shown in Table 1 (for example, Experimental example 1 shown in Table 1
(Pair-to-pair, pair-to-pair, pair-to-pair combination) in
A value obtained by subtracting the standard value defined in Category 5 of ISO / IEC-IS11801 was calculated, and this value was calculated for each combination, and the total frequency band of the standard shown in Table 2 (11 in Table 2
Frequency). Then, even in the worst case, it is a problem whether or not the standard value defined in Category 5 of ISO / IEC-IS11801 shown in Table 2 can be cleared. Therefore, for each combination of pair 14, 11 obtained in all frequency bands was obtained. The minimum value was taken as the near-end crosstalk level of each combination from the measured values-standard values.

The experimental results are digitized as described above,
The combination of the twist pitch of the pair 14 obtained as a result,
The relationship with the near-end crosstalk attenuation amount in each combination is shown in FIG. 4 and evaluated. It should be noted that for each experimental example,
There were 6 combinations, and data were collected for 15 experimental examples, so a total of 90 data could be obtained. For example, for experimental example 15, as shown in Table 1, four pairs of 14 Since the twist pitch values of are equal,
The near-end crosstalk attenuation amounts obtained for the six combinations 14 in total are all overlapped and displayed at only one point in the plot (see the plot above 1 on the horizontal axis in FIG. 4). Also in the combination of the above, the plots are overlapped and shown for the ratio of the twist pitch of 14 and the obtained near-end crosstalk attenuation amount being a minute difference.

In FIG. 4, the abscissa represents the twist pitch ratio of pair 14, and the ordinate represents the measured value of the near-end crosstalk attenuation amount obtained for each combination of pair 14 shown in Table 2 in accordance with ISO / IEC.
-Shows the evaluation of the near-end crosstalk attenuation amount of the combination of pair 14 in each experimental example by taking the minimum value in the entire frequency band of the value obtained by subtracting the standard value defined by Category 5 of IS11801.

Therefore, in FIG. 4, the vertical axis is OdB.
The above values indicate that the measured value was equal to or higher than the standard value (that is, the measured value ≧ the standard value), and the standard value was cleared. Moreover, in this case, each plot in FIG. 4 shows the minimum value in the values obtained by subtracting the standard value from the measured value of the near-end crosstalk attenuation amount obtained in the entire frequency band for each combination of pair 14. Therefore, when this plot is OdB or more on the vertical axis, it indicates that the standard value can be cleared in all other frequency bands in the combination of the pair 14.

The horizontal axis of FIG. 4 shows the ratio of the twist pitches of the pair 14, that is, for example, the twist pitch of one pair T _I is P _I and the twist pitch of the other pair T _II is P _II . Then, since P _I / P _II is shown, when the horizontal axis is smaller than 1, it indicates that P _I <P _II , and when the horizontal axis is larger than 1, P _I > P _II It indicates that there is.
As shown in Table 2, since the twist pitches of the pair 14 of Experimental Example 15 were all set to be equal to 15 mm (that is, P _I = P _II ), a plot for the combination of Pair 14 in Experimental Example 15 was obtained. Is displayed on the horizontal axis 1 as shown in FIG. 4, while in other Experimental Examples 1 to 14, the twist pitches of the pair 14 are all set to be different. In Experimental Examples 1 to 14, P _I / P _II = 1 cannot be obtained, and in FIG. 4 as well, all data other than the pair 14 combination in Experimental Example 15 are at points other than 1 on the horizontal axis. Is plotted in.

In evaluating the experimental results shown in FIG. 4, first, the measured value of the near-end crosstalk attenuation amount is ISO / IEC-.
+ For the standard value defined in Category 5 of IS11801
We sought a combination of 14 pairs that could have a 9 dB margin. The reason why the margin of +9 dB is set is as follows.

In the present invention, as described above, first, in order to obtain good transmission characteristics in high-speed data communication such as 156 Mbps ATM LAN, 156 MHz.
ACR value (near end crosstalk attenuation-attenuation) at +10
It must be dB. Therefore, for that purpose, it is necessary to find out how much near-end crosstalk attenuation amount should be secured. In order to secure +10 dB in the ACR value, it is necessary to improve the characteristics of one or both of the near-end crosstalk attenuation amount and the attenuation amount. That is, the near-end crosstalk attenuation amount is increased, the attenuation amount is decreased, or both of them are performed. In the communication cable 10, in order to reduce the attenuation amount, a separate component such as a shield is provided. What is needed, on the other hand, in general, the near-end crosstalk attenuation can be improved by properly selecting the twist pitch of the pair 14, and in the communication cable 10, near-end crosstalk is mainly a problem. Since it is necessary to sufficiently improve the near-end crosstalk characteristic, the above conditions (1) to (6)
In deriving the equation in, we focused on achieving this goal by improving the near-end crosstalk attenuation.

Regarding the communication cable 10 which can be used for high speed data communication up to 100 Mbps, the attenuation amount and the near end of the electric wire (pair 14) having a characteristic impedance of 100 Ω in Category 5 of EIA / TIA-568A. Regarding the crosstalk attenuation amount, the standard is defined by the following mathematical formula. In this case, ISO / IEC-IS1180, which was a problem in FIG.
In the category 5 standard of No. 1, when the characteristic impedance is 100Ω, this EIA / TIA-5
When the characteristic impedance is 120Ω, the standard value for the near-end crosstalk attenuation amount is the same as the value calculated by the following mathematical expression b). Therefore, the frequency of 156 MHz for the pair 14 having the characteristic impedance of 100Ω and 120Ω.
In order to secure +10 dB as the ACR value at, the measured value of the near-end crosstalk attenuation amount is ISO / IEC-IS.
The following formula a) shows how much margin should be given to the standard value defined by category 5 of 11801.
It searched for from the numerical value calculated by applying Numerical formula b).

A) Attenuation: ATT (f) = K1√ (f) + K2
・ F + K3 / √ (f) b) Near-end crosstalk attenuation: NEXT (f) = NEXT (0.772) −15
log (f / 0.772) In the above formula, K1, K2, and K3 are constants,
K1 = 1.967, K2 = 0.023, K3 = 0.050, respectively. Further, f indicates a frequency (unit: MHz).

This standard is applied only in the range up to the frequency of 100 MHz, and here, as a demonstration, the frequency of 100 MHz is substituted into the above formula to obtain 10
Let's calculate the attenuation and the near-end crosstalk attenuation at 0 MHz. First, the attenuation is ATT (100) = K1 ・ √ (100) ＋ K2 ・
100 + K3 / √ (100) = 21.97 to 21.97 dB. The near-end crosstalk attenuation is NEXT (100) = NEXT (0.7
72) -15log (100 / 0.772) = 64-31.68 ≒ 3
2 to 32 dB, and ISO / IE shown in Table 2 determined according to Category 5 of EAI / TIA-568A
100MH defined by C-IS11801 Category 5
As per the z standard (see Table 2). In addition, in the mathematical expression b) regarding the near-end crosstalk attenuation, “NEXT (0.772)
] Becomes “64” from the numerical value shown in the uppermost row of Table 2.

Next, from the values of the attenuation amount and the near-end crosstalk attenuation amount, the ACR value at 100 MHz (NEXT (100)
-ATT (100)) is obtained, 32-21.97 = 10.0
Since it is 3 (dB), at a frequency of 100 MHz, if the standard defined in Category 5 of ISO / IEC-IS11801 is satisfied, it is surely + 10d.
It is understood that the ACR value of B can be secured.

The mathematical expression in the above standard is the frequency 10
It is applied only in the range up to 0 MHz.
When the attenuation at 156 MHz and the near-end crosstalk attenuation are calculated by substituting for, ATT (156) = K1 · √ (156)
+ K2 · 156 + K3 / √ (156) = 28.16 to 28.16
dB, and the near-end crosstalk attenuation is NEXT (156) = NEXT (0.7
72) -15log (156 / 0.772) = 64-34.58 = 2
It becomes 9.42. Therefore, the ACR value is 29.42-
28.16 = + 1.26 (dB), which is far below +10 dB.

Therefore, at a frequency of 156 MHz,
To secure an ACR value of +10 dB or more, simply
It has been found that it is not enough to secure the near-end crosstalk attenuation amount as the mathematical formula of the above-mentioned standard, and it is necessary to further improve the near-end crosstalk attenuation amount from the standard value at the frequency of 100 MHz. As described above, since the standard value of the attenuation amount at the frequency of 156 MHz is ATT (156) = 28.16 (dB), the ACR value at the frequency of 156 MHz is +
28.16 + 10.0 = in order to be 10 dB or more
From 38.16 (dB), the near-end crosstalk attenuation amount is 38.16.
It must be at least dB.

Therefore, considering the margin of the near-end crosstalk attenuation amount of 38.16 dB in comparison with the standard defined in Category 5 of ISO / IEC-IS11801, the mathematical formula defined in the above standard is taken into consideration. The near-end crosstalk attenuation amount at the frequency of 156 MHz calculated by NEXT (156) = 29.42 (dB) is 38.16−29.42 = 8.74≈9 (dB). Therefore, as the near-end crosstalk attenuation amount, ISO / IEC
-If a margin of +9 dB can be provided with respect to the standard value defined by Category 5 of -IS11801, a combination of 14 pairs having the same characteristic impedance,
In other words, a pair of 14 having characteristic impedances of both 100Ω
And a pair 14 of 120Ω each, as the ACR value at a frequency of 156 MHz,
It is considered that +10 dB can be secured.

As described above, ISO / IEC-
In IS11801 category 5, it is stipulated that the near-end crosstalk attenuation amount should be calculated by the above mathematical expression b), but the mathematical standard does not stipulate the attenuation amount. However, ISO / IEC-IS11
In category 801, the characteristic impedance is 12
As the standard value of the attenuation amount at the frequency 100 MHz of the pair 14 of 0Ω, the characteristic impedance is required to be a more severe condition, that is, a lower numerical value than the standard value of the attenuation amount at the frequency 100 MHz of the pair 14 of 100Ω. Therefore, the characteristic impedance is 120Ω for pair 14
Regarding the value of the attenuation at the frequency of 156MHz,
Proportionally, it can be considered that the value is even lower than the value of the attenuation amount calculated by the above equation a) for the pair 14 of characteristic impedance of 100Ω. Therefore, the ACR calculated by subtracting the value of the attenuation amount for the pair 14 having the characteristic impedance of 100Ω from the near-end crosstalk attenuation amount for the pair 14 having the characteristic impedance of 120Ω.
If a value of +10 dB or more can be secured, 1
When the ACR value is calculated by subtracting the attenuation amount for the pair 14 having the characteristic impedance of 20Ω, the difference between the near-end crosstalk attenuation amount and the attenuation amount is even larger, and therefore it is +10 dB without fail.
The above can be secured and there is no problem. In particular, in the present invention, the outer diameter of the insulated electric wire 16 forming the pair 14 is made different to further reduce the amount of attenuation.
There are no problems, and these are also demonstrated by the examples of the present invention described later.

Next, in the present invention, the communication cable 1 in which the signal transmission by the two different applications is the same.
Since it is performed within 0, the characteristic impedance is 100Ω to 1 in consideration of multiple crosstalk from signals transmitted at the same time.
It is also necessary to consider the near-end crosstalk attenuation amount between 4 and the pair 14 having the characteristic impedance of 120Ω. Considering this multiple crosstalk, ISO / IEC-IS118
According to 01, it is necessary to have a margin calculated by the following mathematical expression c) with respect to the standard value of the near-end crosstalk attenuation amount calculated by the mathematical expression b). c) ΔNEXT = 6 + 10log (n + 1) In this mathematical expression c), n indicates the number of units (combination of pair 14) adjacent to each other (combination of pair 14).

In this case, the number of adjacent units indicates, in other words, how many data transmission paths (one on the transmitting side and one on the receiving side) are adjacent from the viewpoint of multiple crosstalk. With respect to this point, in the present invention, taking FIG. 1 as an example, two pairs of characteristic impedances of 100Ω are used.
A combination of L ₁ and 14 L ₂ forms one data transmission path (input / output), and a characteristic impedance of 120Ω is 2
Since one pair of pairs 14H ₁ and 14H ₂ constitutes one data transmission path (input / output), a pair of pairs 14 having different characteristic impedances are adjacent to each other. Therefore, n in the above equation c) is n regardless of which pair 14 is combined.
= 1.

Then, substituting n = 1 into the equation c),
From ΔNEXT = 6 + 10log (1 + 1) = 9 (dB), if a margin of +9 dB can be obtained with respect to the standard value calculated by the above equation b) as the near-end crosstalk attenuation amount, a pair having different characteristic impedances 14 Combination, that is, pair 1 with a characteristic impedance of 100Ω
It is considered that the near-end crosstalk level in the combination of 4 and 120Ω pair 14 can be improved to sufficiently reduce the multiple crosstalk. If the standard value of +9 dB can be cleared in this way, as a result, +10 dB can be secured as the ACR value at the frequency of 156 MHz even between the pairs 14 having different characteristic impedances. it can.

From the above, A at the frequency of 156 MHz
For the combination of pairs 14 with the same characteristic impedance to ensure a CR value of +10 dB and the combination of pairs 14 with different characteristic impedance to reduce multiple crosstalk, ie all four pairs 14 It is considered that the near-end crosstalk level targeted by the present invention can be achieved if a margin of +9 dB with respect to the standard value can be provided as the near-end crosstalk attenuation amount.

From the above point of view, in FIG. 4, it is possible to have a margin of +9 dB with respect to the standard value.
When a combination of No. 4 was searched for, as shown in the hatched area A in FIG. 4, the twist pitch ratio (P _I / P _II ) was P _I <
When P _II (that is, when the horizontal axis is less than 1),
It was found to be a combination of the pair 14 with 0.8 or less (P _I / P _II ≦ 0.8).

When the relationship between the twist pitch P _I and the twist pitch P _II is reversed, and P _I > P _II ,
The values of the near-end crosstalk attenuation amount are equal, and the ratio of the twist pitches in this case is just a reciprocal relation. From this, P
_I <In the case of P _II is that clear the criterion that the standard value + 9 dB if P _I / P _II ≦ 0.8 is the reverse P _I> in the case of P _II, the 0.8 The reciprocal of the numerical value, that is, 1.25, and P _I / P _II ≧ 1.25
Within the range, the standard value of +9 dB can be cleared similarly. In fact, also in FIG.
As shown in the shaded area A ′, the twist pitch ratio (P _I
/ P _II ) is P _I > P _II (that is, the horizontal axis is 1)
1.25 or more (P _I / P _II ≧ 1.2)
In the range of 5), it can be confirmed that the standard of +9 dB is cleared.

Also, paying attention to FIG. 4, here, as shown in the shaded area B, in the range of 0.8 <P _I / P _II <1.25, that is, in the area outside the shaded areas A and A '. Also, a plot is shown at a position where the vertical axis is +9 dB or more, and there is data that clears the standard value of +9 dB. This is a case of a combination of relatively short twist pitches in the twist pitches of the pair 14 which are variously set in Experimental Examples 1 to 15, and therefore, when the value of P _I × P _II is small to some extent. Are shaded areas A and A'in FIG.
The ratio of the twist pitch of pair 14 (P _I / P
Even in the area where _II ) is close to 1x, to some extent the standard value +9 dB
It is speculated that there are 14 pairs of combinations that can clear the criterion.

Confirming this, the standard value +9 dB
In order to search for a region where the above standard can be cleared, a plot of a range where the twist pitch ratio of the pair 14 is 0.8 <P _I / P _II ≦ 0.85 shown in the shaded region B of FIG. 4,
That is, the product of the twist pitches of the pair 14 is calculated as an index for quantifying the magnitude of the twist pitch of the pair 14 by limiting the measurement value related to the combination of the pair 14 and the horizontal axis represents the product of the twist pitches (P _I x P _II ) and shown in FIG. 5, and the relationship between the product (P _I × P _II ) of the twist pitch of the pair 14 and the near-end crosstalk attenuation amount was investigated.

As can be seen from the shaded area C in FIG. 5, in the region where the product (P _I × P _II ) of the twist pitch of the pair 14 is 150 or less (P _I × P _II ≦ 150), the twist of the pair 14 is twisted. It can be confirmed that the standard value of +9 dB can be satisfied even in the range where the pitch ratio is P _I / P _II ≦ 0.85. Also, in this case, similarly, the magnitude relationship between the twist pitch P _I and the twist pitch P _II is reversed and grasped, and P _I > P _II
In this case, the reciprocal of the numerical value of 0.85, that is, 1.18 is taken, and if it is within the range of P _I / P _II ≧ 1.18, similarly, the standard value of +9 dB is cleared. It is considered possible.

In summary of the above experimental results, in order to clear the standard of +9 dB as the near-end crosstalk attenuation amount, when the twist pitch product of the pair 14 is 150 or less (P _I × P _II ≦ 150 ), The twist pitch ratio of 14 to 0.85 or less or 1.18 or more (P _I / P _II ≦ 0.8
5 or P _I / P _II ≧ 1.18) and the product of the twist pitch of the pair 14 is larger than 150 (P
_I × P _II > 150), the twist pitch ratio of 14 is 0.8 or less or 1.25 or more (P _I / P _II ≦ 0.8 or P _I / P _II ≧ 1.25). It turns out that you should choose.

Then, next, based on these experimental results, the total of the two pairs 14 of low characteristic impedance and the two pairs 14 of high characteristic impedance, four pairs 14
Considered the proper combination of.

First, if the above-mentioned selected region is satisfied, a sufficient near-end crosstalk characteristic can be obtained. However, for all four pairs 14, that is, for the pairs 14 set to either high or low characteristic impedance. , Both, when the product of the twist pitch of the pair 14 is set to be 150 or less, or larger than 150, the twist pitch values of the pair 14 become close to each other, and accordingly, twists in various combinations of the twist pitch of the pair 14 are increased. Since the pitch ratio tends to approach 1 time, when selecting the twist pitch of the pair 14, considering that the above-mentioned twist pitch ratio of the pair 14 is satisfied,
The combinations of twist pitches of the pair 14 that can be selected will be very limited. That is, the probability that the twist pitch values of the four pairs 14 overlap becomes high, and when the twist pitch values approach each other in this way, the optimum twist pitch ratio of the pair 14 obtained as a result of the above experiment should be ensured. Therefore, a sufficient near-end crosstalk characteristic cannot be obtained, and the selection region of the pair 14 combination becomes narrow.

If all four pairs 14 are set so that the product of the twist pitches of the pair 14 is larger than 150, the twist pitch value of the pair 14 becomes too large, and the twist of the pair 14 collapses. Is not preferable from the viewpoint of. Conversely, even if the product of the twist pitches of the pairs 14 is set to 150 or less for all four pairs 14, the insulating layer 20
It is not preferable from the viewpoint of crushing.

Therefore, of the two pairs of four pairs 14 having different characteristic impedances, the twist pitch of the two pairs 14 having one of high and low characteristic impedances is a combination of relatively small values P _I × P _II By selecting from the region of ≦ 150, the selection range of the twist pitch of the two pairs 14 having the other characteristic impedance is widened, and the optimum twist pitch ratio of the pair 14 obtained as a result of the above experiment is surely ensured. I was able to do it. Further, as a result, the maximum value of the twist pitches of the selected four pairs 14 can be made relatively small, so that the deterioration of the near-end crosstalk characteristics due to the twist collapse of the pairs 14 can be prevented. .

From this fact, the twist pitches P _I and P _II in the mathematical formulas obtained as a result of the above-mentioned experiments are respectively _{defined by} the twist pitch P _L1 of the pair T _L1 and T _L2 of low characteristic impedance,
Replacing with P _L2 , as condition (1) and condition (2),
First, under the condition (1), “a pair of low characteristic impedance vs. T
The twist pitches P _L1 and P _L2 of _L1 and T _L2 are P _L1 × P _L2 ≦ 15
On the other hand, in the condition (2), the twist pitches P _H1 and P _H2 of the pair of high characteristic impedances T _H1 and T _H2 are within the range of P _H1 × P _H2 > 150. It is classified as "selected".

In this case, the product of the twist pitches has a characteristic impedance of either high or low.
Since one pair 14 can be divided into 150 or less,
The conditions ((1) and (2)) can be considered in the same way when the selection region regarding the twist pitch of the pair 14 of high and low characteristic impedances is reversed. Therefore, the conditions (4) and (5) are pitch P _L1, P _L2 twist (4), the pair of "low characteristic impedance T _L1, T _L2 is, P _L1 × P
_L2 > 150 ”, but under the condition (5), the twisting pitches P _H1 and P _H2 of the pair of high characteristic impedances T _H1 and T _H2 are in the range of P _H1 × P _H2 ≦ 150. It is selected from within ”.

Further, as described above, there is no problem if the standard of +9 dB can be cleared for all combinations of four pairs 14. Therefore, under these preconditions, first, for the combination of the pair 14 having the same characteristic impedance, according to the above experimental results, when the product of the twist pitches of the pair 14 is larger than 150, P _I <P _{When II} , P _I / P _II ≦ 0.8, P _I >
When P _II is selected so that P _I / P _II ≧ 1.25, and when the product of the twist pitch of the pair 14 is 150 or less, when P _I <P _II , P _{I I} / P _II ≦ 0.85,
When P _I > P _II , it has been found that selection can be made so that P _I / P _II ≧ 1.18. Therefore, the twist pitches P _I and P _II in this equation have low characteristics. twist pitch P _L1 pair T _L1, T _L2 of the impedance, P _L2, a pair of high characteristic impedance T _H1, T _H2 twisting pitch P _H1, P _H2
, And the mathematical expressions ,, and in the conditions (1) and (2) and the mathematical expressions ',', ', and' in the conditions (4) and (5) are derived.

In this case, the mathematical expression and the mathematical expression in the condition (1) are divided into applicable ranges depending on whether P _L1 <P _L2 or P _L1 > P _L2 , and similarly, the condition (2)
The formulas and formulas in are also P _H1 <P _H2 , or P _H1
Since the application range is divided depending on whether or not> P _H2 , the formulas and the formulas cannot be applied simultaneously and the formulas and the formulas cannot be applied at the same time in one communication cable 10 and have the same characteristic impedance. Only one of the pair 14 is applied. The same applies to the condition (4) and the condition (5).

On the other hand, the combination of the mathematical expressions between the condition (1) and the condition (2) in one communication cable 10, that is, between the pairs 14 of different characteristic impedances, is the same in one set, that is, the same. Since there is no problem if the ratio of the twisting pitch of the characteristic impedance 14 to the twisted pitch of the equation 14 is satisfied, the equation or the equation, or the equation or the equation,
(B) Formula and formula, (c) Formula and formula, (d)
Any of a total of four formulas and formulas may be established. This also applies to the conditions (4) and (5).

Next, a pair 14 having different characteristic impedances is used.
The conditions concerning the ratio of the twist pitch in the combination of are examined. This is because the near-end crosstalk attenuation of the combination of the pair 14 between different characteristic impedances is also ISO / IEC-IS1 in consideration of multiple crosstalk, as described above.
This is because the twist pitches of the pairs 14 do not overlap between the pairs 14 having different characteristic impedances in order to have a margin determined by 1801. As described above, the selected region is divided between the pairs 14 having different characteristic impedances with the product value of the twist pitch of the pair 14 being 150 as a boundary. However, it is numerically different only by this condition. Since the twist pitch values of the pair 14 of characteristic impedances may overlap, it is necessary to consider an appropriate value of the twist pitch ratio of the pair 14.

The combinations of the pairs 14 of different characteristic impedances are (A) P _L1 and P _H1 , (B) P _L1 and P _H2 ,
There are four possible combinations of (C) P _L2 and P _H1 , and (D) P _L2 and P _H2 . However, (I) of these combinations, a pair 14 selected such that the product of the twist pitch is 150 or less in one communication cable 10.
The product of the maximum value and the twist pitch in the combination of is 150
The relationship with the minimum value in the combination of pairs 14 selected to be super (the relationship between PL _(Max) and PH _(Min) or P
_It is considered sufficient to study only the relationship between _{L (Min)} and PH _(Max) .

The reason is that the near-end crosstalk is usually affected by the twist pitch ratio of the pair 14, and in particular, the closer the twist pitch value is, the lower the near-end crosstalk level is. If the near-end attenuation can be secured, a sufficient difference in the near-end crosstalk attenuation can be obtained for other combinations of the pair 14 having different characteristic impedances because the twist pitch value of the pair is further large. Is.

(II) Regarding the relationship between the twist pitches of the pair 14 having different characteristic impedances, the product of the twist pitches of the pair 14 obtained from the above experimental results is ">1".
50 ”, the ratio of the twist pitch of 14 pairs required, that is, when P _I <P _II , P _I / P _II ≦ 0.
8. When P _I > P _II , it is considered that P _I / P _II ≧ 1.25 should be satisfied. The reason is that, firstly, between different characteristic impedances, one of the twist pitches of the two pairs 14 to be compared must be "P ₁ × P ₂ >150".
The product of the twisting pitches of the two contrasting pairs 14 between these different characteristic impedances is usually considered to be included in a region larger than 150 as a result of being selected from the range.

Secondly, as can be seen from the results of the above experiment, the combination of the pair 14 (see the formulas, ',') in which the product of the twist pitches of the pair 14 is ">150" is The twist pitch ratio of the pair 14 is set to be farther from 1 than the combination of the pair 14 of “≦ 150” (see the equations, ', and'), that is, the difference in the twist pitch value of the pair 14 is It is necessary to set it so that it becomes large (a twist pitch ratio of 0.85 or less or 1.25 or more when 150 or less, whereas it is 0.8 when it exceeds 150.
Or less or 1.18 or more). Accordingly, a) the twist pitch ratio of the pair 14 in which the twist pitch product of the pair 14 exceeds 150 is b) the twist pitch ratio region of the pair 14 in which the twist pitch product of the pair 14 is 150 or less. Must be included in the range b), and is a narrower and more severe range from the range of b). Therefore, the difference between the twist pitch values of the two pairs 14 to be compared is 0. This is because a sufficient near-end crosstalk attenuation amount can be secured by increasing the value to 8 or less or 1.25 or more.

From the above items (I) and (II), first,
In the cases of condition (1) and condition (2), pair 14
The product of the twist pitches of 150 or less is the pair T _L1 and T _L2 of low characteristic impedance, and the product of the twist pitch of pair 14 exceeds 150 is the pair T _H1 and T _{H2 of} high characteristic impedance. And these twist pitches P _L1 and P _L2
If, twist pitch P _H1, P to and from the _H2, the closest is the maximum value P _{L (Max)} of the twisting pitch P _L, twist pitch P
_{It is} the minimum value P _{H (Min)} of _H. In this case PL _(Max) <P
_{Since H (Min)} , as the condition (3), the mathematical formula obtained from the above experimental results, and when P _I <P _II , P _I / P _II
Replacing P _{I (} ≦ 0.8 ₎ with P _{L (Max)} and P _II with P _{H ( Min)} , we derived the formula P _{L (Max)} / P _{H (Min)} ≦ 0.8. .

[0090] In this case, P _{L (Max)} is per pair T _L1, T _L2 of low characteristic impedance, in a case where a P _L1 <P _L2 (if formulas), next to P _L2, conversely, P _L1 ＞
When it becomes P _L2 (in the case of mathematical expression), it becomes P _L1 . Similarly, P _{H (Min)} is also a P _H2 in the <if a P _H2 next P _H1 (in the case of the equation), P _H1> P _H1 if a P _H2 (in formula).

The above is the conditions (1) and (2),
The same applies to the conditions (4) and (5) in which the selected region of the product of the twist pitches of the pair 14 having high and low characteristic impedances is simply set to the opposite. In this case, in the cases of the conditions (4) and (5), the product of the twist pitch of the pair 14 is 150 or less.
High characteristic impedance pair T _H1 , T _H2 , pair 14
The product of the twisting pitches of over 150 is the low characteristic impedance pair T _L1 and T _L2 , and the twisting pitches P _H1 and P _H2 and the twisting pitches P _L1 and P _L2 are closest to each other. to the maximum value P _{H (Max)} of the twist pitch P _H, the minimum value P _L of twisting pitch P _{L (Min).} In this case PL _(Min)
> P _{H (Max)} , the condition (6) is obtained by the mathematical formula obtained from the above experimental result. When P _I > P _II , P _I /
P _I of P _II ≧ 1.25 is P _{L (Min)} , and P _II is P
_By substituting for _{H (Max),} the equation'P _{L (Min)} / P _{H (Max)} ≧ 1.25 was derived.

In these equations, ', the denominator and the numerator of the twist pitch ratio are replaced, and
"P _{H (Min)} / P _{L (Max)} ≥1.25 (mathematical formula)", "P
_{H (Max)} / PL _(Min) ≦ 0.8 (mathematical formula ') ”is technically the same obvious matter, and is merely a difference in terms of expression. Only the pairs of low characteristic impedances 14 are expressed as numerator for the combinations between different characteristic impedance pairs 14.

Conditions (1) to (6) in the present invention
Are derived as described above. Note that these conditions are always applied in a combination of the conditions (1) to (3) or a combination of the conditions (4) to (6). For example, the condition (1) and the condition ( 4) or (5), or the combination of condition (2) and condition (4) or (5) is not applicable to the present invention, as can be seen from the process of deriving the above conditions.

As described above, in order to set the ACR value at the frequency of 156 MHz to +10 dB and to secure the margin defined by ISO / IEC-IS11801 for the multiple crosstalk characteristics, the amount of attenuation of the near-end crosstalk is increased by 14 pairs. The reason for properly selecting the twist pitch is to obtain good transmission characteristics in high-speed data communication while having a small diameter, light weight, and sufficient flexibility. That is, each pair 14 is shielded and
It may be possible to improve the insulation between the two to improve the near-end crosstalk attenuation amount. However, in this case, the diameter of the communication cable 10 is large and the weight is heavy, and the communication cable 10 is required to some extent. This is because there is a problem of lack of flexibility, which further leads to an increase in cost.

Furthermore, the embodiment of the present invention in which the twist pitch of the pair 14 is selected from the region satisfying the above conditions,
To prove its effect.

Specifically, the conductor 18 has an outer diameter of 0.5.
An 11 mm annealed copper wire was used. Then, the two pairs 14L ₁ and 14L ₂ having a characteristic impedance of 100Ω were formed from the conductor 18 and the two-core insulated electric wire 16 having an outer diameter of 0.94 mm in which the insulating layer 20 made of polyethylene was coated. On the other hand, two pairs of 1 with characteristic impedance of 120Ω
4H ₁ and 14H ₂ have an outer diameter of 1.1 which is obtained by covering the same conductor 18 with an insulating layer 20 made of 45% expanded polyethylene.
It was formed from a 5 mm 2-core insulated wire 16.

In this case, as described above, the two pairs 14H ₁ and 14H having the characteristic impedance of 120Ω are used.
_Since the insulated wire 16 forming ₂ has the large outer diameter and the insulating layer 20 made of foamed polyethylene, the insulating layer 20 is easily crushed. Therefore, it is desirable to set the twist pitch of the pair 14 to be long. Therefore, in this embodiment, the combination of the conditions (1) to (3) is selected, and the two pairs 14L ₁ and 14L ₂ having the characteristic impedance of 100Ω are selected.
The twist pitches P _L1 and P _L2 are selected from the range of P _L1 × P _L2 ≦ 150.

The twist pitch of each pair 14 was selected from the range satisfying the above conditions (1) to (3) as follows. First, from the region where P _L1 × P _L2 ≦ 150, P _L1 is set to the minimum value (this twist pitch P _L1 is 4
It is also the minimum value of the twist pitch of one pair 14. ), P _L1 =
In order to make the maximum value of the twist pitches of the four pairs 14 as small as possible by setting the twist pitch as small as 9 mm, the mathematical expressions in the above conditions (1) to (3) are mutually satisfied. We decided to select the smallest value of.

[0099] That is, among the pair 14L ₁ and has a characteristic impedance of the same 100 [Omega, twisted next higher twist pitch P _L2 (4 one pair 14 of twist pitch of the pitch P _L1, 2
The second smallest and the third largest twist pitch) are P _L2 ≧ P _L1 /0.85 from P _L1 / P _L2 ≦ 0.85 (mathematical expression) when P _L1 <P _{L2 in} the condition (1). ≧ 9 / 0.85 ≧ 1
It was 0.58 mm, and was set to 11 mm as the minimum value of 10.58 mm or more.

On the other hand, the twist pitch P _H1 and the twist pitch P _{H2 of the two} pairs of high characteristic impedances 14H ₁ and 14H ₂
And P _H1 <P _H2, and similarly, the twist pitch P _H1 of the pair 14H ₁ which becomes the next largest after P _L1 is P _H1 of the condition (3).
_{From L (Max)} (= P _L2 ) / P _{H (Min)} (= P _H1 ) ≦ 0.8 (mathematical formula), P _H1 ≧ P _L2 /0.8 ≧ 11 / 0.8 ≧ 13.
And 14mm than 75, (the twisting pitch P _H2, also the maximum value of the twist pitch of the four pairs 14.) Or the twisting pitch P _H2, when the conditions of P _H1 <P _H2 (2), P _H1 / P _H2
From ≦ 0.8 (mathematical formula), P _H2 ≧ P _H1 /0.8 ≧ 14 /
From 0.8 ≧ 17.5, it was set to 18 mm. Thus, the twist pitches P _L1 , P _L2 , P _{H1 of} the four pairs 14 are
_Let P _H2 be P _L1 = 9 mm, P _L2 = 11 mm,
P _H1 = 14 mm and P _H2 = 18 mm were set.

Further, by setting in this way, all the combinations of the pair 14 can satisfy the mathematical expressions in the above conditions (1) to (3). As for the product of the twist pitch, the pair of low characteristic impedances 14L ₁ and 14L ₂ is 9 × 11.
= 99 and less than 150, 14 × 18 = 25 for pairs 14H ₁ and 14H ₂ having high characteristic impedance.
2 can be made larger than 150, and the selected area of both twist pitches can be divided by the product of the twist pitches at the boundary of 150. That is, in selecting the actual twist pitch, the mathematical expression in the condition (3) and the condition (6)
If it is set so as to satisfy the formula 'in
The prerequisites for the product of the twisted pitch of can also be satisfied. This is because, in the first place, these mathematical expressions ′ are imposed as a condition so that the twist pitch values of the pair 14 having different characteristic impedances do not overlap.

As described above, a total of four pairs 14 in which the value of the twist pitch is selected are interleaved with polyethylene 2.
Two twisted pairs 14 having the same characteristic impedance are arranged diagonally with respect to 2 as a center.
And Then, a press winding 28 is applied to the aggregated twisted layer 12, and a polyester tape 26 having aluminum adhered to both surfaces thereof is wrapped and wrapped to form a shield layer 24. Then, the communication cable 10 shown in FIG. 1 was manufactured by coating the sheath 32 made of polyvinyl chloride for protecting the collective twisted layer 12 and the shield layer 24.

In the above examples, first, the near-end crosstalk attenuation amount was measured for the combination of the pair 14 having the same characteristic impedance. First, the near-end crosstalk attenuation amount was measured for the combination of pair 14L ₁ and pair 14L ₂ having characteristic impedance of 100Ω, and the result is shown in FIG. Specifically, for the combination of 14 pairs, a total frequency band defined by Category 5 of ISO / IEC-IS11801 shown in Table 2 (11 frequencies shown in Table 2) and a total of 12 of 156 MHz which are problems in the present invention. The near-end crosstalk attenuation was measured at frequency. As can be seen from FIG. 6, the near-end crosstalk attenuation amount relating to the combination of the pair 14L ₁ and the pair 14L _{2 having} the characteristic impedance of 100Ω is ISO / IEC-IS11801 over the entire frequency band.
It is possible to secure a margin of +9 dB with respect to the standard value of the near-end crosstalk attenuation amount defined in category 5 of
Near-end crosstalk attenuation at 6MHz is also +9 with respect to the standard value
It was possible to secure a margin of dB.

[0104] Second, the characteristic impedance per pair combinations 14H ₁ pair 14H ₂ of 120 Ohm, in the same manner, by measuring the near-end crosstalk attenuation, and the results are shown in Figure 7. As can be seen from FIG. 7, the near-end crosstalk attenuation amount for the combination of the pair 14H ₁ and the pair 14H ₂ with the characteristic impedance of 120Ω is also ISO / I over the entire frequency band.
A margin of +9 dB can be secured with respect to the standard value of the near-end crosstalk attenuation amount defined in EC-IS11801 category 5, and in particular, a margin of +9 dB with respect to the standard value can also be secured for the near-end crosstalk attenuation amount at 156 MHz. I was able to.

Next, the ACR value was calculated based on the near-end crosstalk attenuation amount thus obtained for the pair 14 combination. First, a pair 14 with a characteristic impedance of 100Ω
The ACR value for the combination of L ₁ and 14 L ₂ was calculated for each frequency and shown in FIG. As can be seen from FIG. 8, for the combination of the pair 14L ₁ and the pair 14L _{2 having} the characteristic impedance of 100Ω, the ACR value of +10 dB or more could be secured at any frequency.

Secondly, similarly, the ACR value for the combination of the pair 14H ₁ and the pair 14H ₂ having the characteristic impedance of 120Ω was calculated for each frequency and shown in FIG. As can be seen from FIG. 9, regarding the combination of the pair 14H ₁ and the pair 14H ₂ of the characteristic impedance of 120Ω, the ACR value is +1 at any frequency.
It was possible to secure 0 dB or more.

In particular, as can be seen from FIGS. 8 and 9, it was possible to secure an ACR value of +10 dB or more at a frequency of 156 MHz, which is a particular problem in any combination of the pairs 14 of characteristic impedances. Therefore, it is understood that if the twist pitch of the pair 14 is selected from the range shown in the present invention, good transmission characteristics can be obtained in high-speed data communication of 156 Mbps.

Next, a pair 14 having different characteristic impedances is used.
The near-end crosstalk attenuation amount is measured for each of the combinations (total of 4 combinations), and for each combination of the pair 14 as in FIGS. 6 and 7, the ISO / IEC-IS11801 shown in Table 2 is obtained.
All frequency bands defined in Category 5 of
Frequency) and 156 MHz which is a problem in the present invention
The near-end crosstalk attenuation amount was measured at a total of 12 frequencies, and the results are shown in FIG. As can be seen from FIG. 10, even if the near-end crosstalk attenuation amount for any combination of the pairs 14 having different characteristic impedances is taken, it is within the standard value of the near-end crosstalk attenuation amount defined by Category 5 of ISO / IEC-IS11801 over the entire frequency band. To + 9d
B margin can be secured, especially 156 MH
The near-end crosstalk attenuation amount at z was also able to secure a margin of +9 dB with respect to the standard value. Thereby, if the twist pitches regarding the combination of the pairs 14 of different characteristic impedances are selected so as to satisfy the mathematical expression of the present invention, in particular, the mathematical expression in the condition (3) and the mathematical expression ′ in the condition (6), multiple crosstalk is caused. IS determined in consideration
It can be seen that the margin defined by O / IEC-IS11801 can be secured, and good multiple crosstalk characteristics can be secured, and two applications with different characteristic impedances can be supported.

[0109]

According to the present invention, as described above, for example, in a communication cable having an assembled twisted layer composed of four pairs, one pair of two pairs having a characteristic impedance of 100Ω and a pair of 120Ω are provided. Two pairs having characteristic impedance are set as one set, and these pairs are combined, and two pairs of two types having different characteristic impedances are diagonally arranged and twisted, so that pairs having different characteristic impedances are twisted. Since they serve as spacers, and a distance can be provided between pairs having the same characteristic impedance, a single communication cable can be used for applications with different characteristic impedances while ensuring good near-end crosstalk characteristics. There is a real advantage that the communication cable can be effectively used.

In this case, in particular, when the twist pitches of a plurality of pairs are numerically limited as described above, the twist pitches of adjacent pairs are always different, and as shown in the above experimental example and the embodiment of the present invention. , Since each pair is twisted with the optimum twist pitch obtained as a result of the experiment, the near-end crosstalk attenuation is improved not only between pairs having the same characteristic impedance but also between pairs having different characteristic impedances. ISO on multi-crosstalk because it can
The margin defined by / IEC-IS11801 can be secured, and one communication cable can be used for two applications with different characteristic impedances while securing good multiple crosstalk characteristics and attenuation.

Further, as shown in the above experimental example and the embodiment of the present invention, by improving the characteristics of the near-end crosstalk attenuation amount and the attenuation amount, at the same time, 156M in the communication cable 100m is obtained.
The ACR value at Hz can be set to +10 dB or more, and there is a practical advantage that good transmission characteristics can be obtained even in high-speed data communication of 100 Mbps or more, particularly 156 Mbps.

Further, in these cases, when the outer diameters of the insulated electric wires forming the pair are made different as described above, when the press winding or the shield layer is applied on the collective twisted layer, Since the occupancy of air increases, the attenuation can be reduced by reducing the dielectric constant, and better transmission characteristics can be obtained. In particular, the value obtained by subtracting the attenuation from the near-end crosstalk attenuation There is a real benefit that is effective in improving the ACR value.

[Brief description of drawings]

FIG. 1 is a sectional view of a communication cable of the present invention.

FIG. 2 is a sectional view of a pair used in the present invention.

FIG. 3 is a schematic sectional view of a unit type communication cable in which the communication cable of the present invention is one unit.

FIG. 4 is a plot diagram showing a relationship between a near-end crosstalk attenuation amount obtained for a pair combination in an experimental example related to the present invention and a twist pitch ratio of the pair.

FIG. 5 shows a near-end crosstalk attenuation amount obtained for a pair combination having a twist pitch ratio of 0.8 or more and 0.85 or less among the pair combination in the experimental example of the present invention, and the twist of the pair. It is a plot figure which shows the relationship with the product of a pitch.

FIG. 6 is a plot diagram showing measured values of near-end crosstalk attenuation amount obtained for a combination of pairs having a characteristic impedance of 100Ω in the example of the present invention.

FIG. 7 is a plot diagram showing measured values of near-end crosstalk attenuation amount obtained for a combination of pairs having a characteristic impedance of 120Ω in the example of the present invention.

FIG. 8 is a plot diagram showing ACR values obtained for a pair combination having a characteristic impedance of 100Ω in the example of the present invention.

FIG. 9 is a plot diagram showing ACR values obtained for a pair combination having a characteristic impedance of 120Ω in the example of the present invention.

FIG. 10 is a plot diagram showing measured values of near-end crosstalk attenuation obtained for a combination of a pair of characteristic impedances of 100Ω and a pair of 120Ω in the embodiment of the present invention.

[Explanation of symbols]

10 Communication Cable 12 Collected Twisted Layer 14 Pair 14L ₁ and 14L ₂ Pair with Low Characteristic Impedance 14H ₁ and 14H ₂ Pair with High Characteristic Impedance 16 Insulated Wire 18 Conductor 20 Insulation Layer 22 Interposition 24 Shield Layer 26 Bonded Aluminum on Both Sides Polyester tape 28 Presser foot 30 Braid 32 Sheath 40 Communication cable (unit type) 42 Unit 44 Interposer 46 Presser foot 48 Sheath

Claims (4)

[Claims] 1. A communication cable comprising a collective twist layer formed by collectively twisting a plurality of pairs formed by twisting two-core insulated electric wires so that adjacent pairs have different twist pitches. The pair is composed of at least two pairs having different characteristic impedances, with two pairs having the same characteristic impedance as one pair, and the plurality of pairs are twisted by arranging the two pairs of the one pair diagonally. A communication cable characterized in that 2. The communication cable according to claim 1, wherein the two pairs of the characteristic impedances are different from each other.
Two pairs of lower characteristic impedance T _L1 , T _L2
The twist pitches P _L1 and P _L2 and the twist pitches P _H1 and P _{H2 of the} two pairs T _H1 and T _H2 having the higher characteristic impedance satisfy the following conditions (1) to (3), respectively. A communication cable characterized by being selected from areas that satisfy at the same time. Condition (1) The twist pitches P _L1 and P _L2 of the pair of low characteristic impedance T _L1 and T _L2 are selected from the range of P _L1 × P _L2 ≦ 150, and when P _L1 <P _L2 , P _L1 / P _L2 ≦ 0.85 (Mathematical formula) When P _L1 > P _L2 , P _L1 / P _L2 ≧ 1.18 (Mathematical formula) Condition (2) High characteristic impedance pair T _H1 , T _H2 twist pitch P _H1 and P _H2 are selected from the range of P _H1 × P _H2 > 150, and when P _H1 <P _H2 , when P _H1 / P _H2 ≦ 0.8 (formula) P _H1 > P _H2 Is P _H1 / P _H2 ≧ 1.25 (Equation) Condition (3) Low characteristic impedance pair T _L1 , T _L2 twist pitch P _L1 , P _L2 maximum value P _{L (Max)} and high characteristic impedance The minimum value P _{H (Min)} of the twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 satisfies the following relationship. P _{L (Max)} / P _{H (Min)} ≦ 0.8 (mathematical formula) 3. The communication cable according to claim 1, wherein, of the two pairs of pairs having different characteristic impedances,
Two pairs of lower characteristic impedance T _L1 , T _L2
The twist pitch P _L1, P _L2 of the two pairs of set towards the characteristic impedance is high T _H1, T _H2 twisting pitch P _H1, and the P _H2, respectively the following conditions (4) to condition (6) A communication cable characterized by being selected from areas that satisfy at the same time. Condition (4) The twist pitches P _L1 and P _L2 of the pair T _L1 and T _L2 of low characteristic impedance are selected from the range of P _L1 × P _L2 > 150, and when P _L1 <P _L2 , P _L1 / P _L2 ≤ 0.8 (Equation ′) When P _L1 > P _L2 , P _L1 / P _L2 ≧ 1.25 (Equation ′) Condition (5) High characteristic impedance pair T _H1 , T _H2 twist The pitches P _H1 and P _H2 are selected from the range of P _H1 × P _H2 ≦ 150, and when P _H1 <P _H2 , P _H1 / P _H2 ≦ 0.85 (equation ') P _H1 > P _{When H2} , P _H1 / P _H2 ≧ 1.18 (Equation ') Condition (6) The minimum value P _{L (Min)} of the twist pitches P _L1 and P _L2 of the pair of low characteristic impedance T _L1 and T _L2 , The maximum value P _{H (Max)} of the twist pitches P _H1 and P _H2 of the pair T _H1 and T _H2 of high characteristic impedance satisfies the following relationship. P _{L (Min)} / P _{H (Max)} ≧ 1.25 (Formula ') 4. The communication cable according to claim 1, wherein one pair of two pairs having the same characteristic impedance has an outer diameter of a two-core insulated wire that constitutes the pair. And a plurality of pairs having different characteristic impedances have different outer diameters of the insulated wires forming the pairs.