JPH11126518A - Signal wire for data transmission, signal wire bundle for data transmission, and cable for data transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently suppress transmission of high frequency noise components. SOLUTION: The outer circumferential side of an SCSI cable 800 is covered with a shield layer 81 which comprises a ferromagnetic metal plating layer (e.g. a pure iron layer) with relatively high resistivity formed on the outer circumference of non- magnetic wires (e.g. copper wires) with relatively low resistivity and is formed by transversely coiling or knitting the plated non-magnetic wires. A plurality of signal transmission wires 100 for data transmission produced by forming ferromagnetic metal plating layer (e.g. pure iron layer) 2 with relatively low resistance on the outer circumferences of non-magnetic signal conductive wires 1 (e.g. copper wires) with relatively low resistance are bundled and signal wire bundles 300A, 300B for data transmission produced by forming insulating layers 3 on the outer circumference of the bundles of the signals transmission wires 100 are pair-twisted to give pair-twisted signal wire bundles for data transmission. The signal wire bundles are arranged in respective arrangement positions A1, B1-B24 in data signal routes. Consequently, since the signal wires, the signal wire bundles and the cable themselves are provided with filter property of dampening high frequency, the data transmission stability and reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission signal line, a data transmission signal wire bundle, and a data transmission cable, and more particularly, to a data transmission signal improved so that transmission of high frequency noise components can be sufficiently suppressed. The present invention relates to a signal line, a data transmission signal line bundle, and a data transmission cable. In particular, SCSI (Small Computer System Interface)
e) Useful for cables.

[0002]

FIG. 14 shows a conventional SCSI cable 90.
FIG. 2 is an explanatory diagram showing an example of a SCSI connection system using 0. In the SCSI connection system C ′, a hard disk device HD is connected to a SCSI interface port of the personal computer P via a SCSI cable 900.

FIG. 15 is a sectional view showing a structural example of the SCSI cable 900. As shown in FIG. As shown in FIG. 15 (a), this SCSI cable 900 has data signal paths at respective positions (indicated by dotted lines) A1, B1, B2,.
, A non-woven tape 90 is spirally wound around the outer periphery, an aluminum polyester tape 91 is spirally wound around the outer periphery, and a braid 92 of a tin-plated copper wire is wound around the outer periphery.
, And an insulating sheath 93 is formed on the outer periphery thereof. As shown in FIG. 15B, the arrangement position A
1, B1 to B24 include a signal line bundle 910 for data transmission.
A, 910B is a twisted pair signal transmission signal bundle. As shown in FIG. 15C, the data transmission signal line bundle 910A (the same configuration is also used for the signal transmission line 910B) is formed by bundling only seven data transmission signal lines 920 each having a tin plating layer 922 formed on the outer periphery of the signal conductor 1. , And an insulating layer 3 formed on the outer periphery thereof.

FIG. 16 is a graph showing the result of measuring the attenuation characteristics of the SCSI cable 900. Note that S
The cable length of the CSI cable 900 is 2 m. From the graph, in the range of the frequency f = 0.3 to 100 MHz,
It can be seen that the attenuation is very small. Also, the frequency f = 1
In the range of 00 MHz to 500 MHz, the attenuation gradually increases as the frequency f increases.
Even at MHz, it is about 8 dB, which means that it is relatively small.

FIG. 17 is an explanatory diagram showing another example of a SCSI connection system using the SCSI cable 900. In the SCSI connection system C ", an LC (Inductance-Capacitance) filter circuit 901 for removing high-frequency noise components is incorporated in the data input / output unit of the hard disk device HD '.

FIG. 18 is a graph showing the result of measuring the attenuation characteristics of the SCSI cable 900 with the LC filter circuit 901 mounted. From the graph, it can be seen that in the range of the frequency f = 0.3 to 100 MHz, the attenuation characteristics are the same as those shown in FIG. 16, and the attenuation is relatively small. Further, the frequency f = 100 MHz to 250 MHz
In the range, the attenuation increases as the frequency f increases, but when the frequency f is equal to or higher than 250 MHz, the attenuation decreases as the frequency f increases. As a numerical example, the attenuation at the frequency f = 250 MHz is about 12 dB, and the attenuation at the frequency f = 500 is about 5 dB.

[0007]

In the above-described conventional SCSI cable 900, as described with reference to FIG.
Since the amount of attenuation with respect to a high frequency of about 200 MHz or more is relatively small (about 8 dB even at 500 MHz), there is a problem that a high frequency noise component is easily transmitted via the data transmission signal wire bundles 910A and 910B. The high-frequency noise component is, for example, an MPU (Microprocessor) of a personal computer.
Unit) is a harmonic component leaked from the unit. Therefore, conventionally, it has been necessary to mount a high-frequency countermeasure component such as a ferrite core on the SCSI cable 900, and there has been an inconvenience that the cost is increased or the cable wire is broken and becomes obstructive.

When the LC filter circuit 901 is used, a certain frequency (in the example of FIG.
(About MHz), the attenuation decreases as the frequency increases, so that a very high frequency (for example, 1 GHz)
Above), it is difficult to sufficiently attenuate the high frequency noise component. In addition, there is a problem that the LC component may cause a high-frequency noise component to wrap around or adversely affect other circuits.

An object of the present invention is to provide a data transmission signal line, a data transmission signal wire bundle, and a data transmission cable which are improved so as to sufficiently suppress transmission of high frequency noise components while preventing adverse effects on others. Is to provide.

[0010]

According to a first aspect of the present invention, a ferromagnetic metal layer having a relatively high resistivity is formed on the outer periphery of a nonmagnetic signal conductor having a relatively low resistivity. A data transmission signal line is provided. In the data transmission signal line according to the first aspect, a current having a frequency of a data signal (generally, at most about several tens Mz) is transmitted with a low loss through a signal conductor having a relatively low resistivity. On the other hand, a loss with respect to a high-frequency current (generally, about 200 Mz or more) increases, and a noise filter characteristic that attenuates a high-frequency noise component in a transmission path can be obtained. The reason why such characteristics are obtained is that high-frequency current tends to concentrate on the outer peripheral side of the non-magnetic signal conductor due to the skin effect, but a relatively high resistivity is applied to the outer periphery of the non-magnetic signal conductor. It is presumed that the high frequency current is rapidly attenuated by the resistance loss of the ferromagnetic metal layer because the ferromagnetic metal layer having the ferromagnetic metal layer is formed. The reason why good characteristics can be obtained by limiting the metal layer to “ferromagnetic” is not clear, but it is presumed that magnetic coupling with the signal conductor is involved. In addition, the fact that "ferromagnetic" metals have originally high shielding performance against high frequencies is also presumed to have a favorable effect. As a result, transmission of a high-frequency noise component can be sufficiently suppressed while transmitting a data signal with low loss. In addition, since there is no change in circuit, it is possible to prevent sneak of high frequency noise components and adverse effects on other circuits.
Furthermore, the higher the frequency, the greater the amount of attenuation in the transmission path, so that high-frequency noise components at very high frequencies (for example, 1 GHz or more) can be sufficiently attenuated.

According to a second aspect of the present invention, in the data transmission signal line having the above configuration, the ferromagnetic metal layer includes at least one of pure iron, iron oxide, nickel, cobalt, and chromium, and a material thereof. The present invention provides a data transmission signal line formed of any one of a composite structure in which a plurality of alloys and the above materials are composited. In the signal line for data transmission according to the second aspect, pure iron, iron oxide,
Since any one of nickel, cobalt, chromium, an alloy containing at least one of these materials, and a composite structure in which a plurality of the above materials are combined is used as the ferromagnetic metal layer, the characteristics (the property of being easily magnetized) as a ferromagnetic material are obtained. It is possible to obtain a good resistance, sufficiently increase the resistivity, and easily obtain excellent noise filter characteristics.

According to a third aspect of the present invention, in the data transmission signal line having the above structure, the thickness of the ferromagnetic metal layer is 0.5 to 2.5 μm. Provide a line. In the signal line for data transmission according to the third aspect, the lower limit of the thickness of the ferromagnetic metal layer is set to 0.5.
Since it is set to μm, the amount of attenuation for high-frequency current can be sufficiently increased, and the shielding performance for high frequency can be sufficiently improved. In addition, since the upper limit of the thickness of the ferromagnetic metal layer is set to 2.5 μm, the ferromagnetic metal layer can be easily formed in a short time by plating or the like, and the hard ferromagnetic metal layer enables the data transmission signal line to be used. Flexibility can be prevented from being impaired.

In a fourth aspect, the present invention provides a data transmission signal line bundle comprising a plurality of data transmission signal lines having the above-described configuration, which are bundled or twisted and an insulating layer is formed on the outer periphery thereof. . In the data transmission signal line bundle according to the fourth aspect, the aggregate of the data transmission signal lines having the above configuration is used as the transmission path of the data signal, so that the transmission loss of the data signal is further reduced and the high frequency noise component is attenuated. The noise filter characteristics to be improved can be improved.

According to a fifth aspect of the present invention, the present invention provides a data transmission signal wire bundle having the above-described structure, wherein a shield layer formed of a horizontal winding or a braid of the data transmission signal line having the above-described structure is formed on the outer periphery of the insulating layer. A data transmission signal line bundle is provided. In the signal line bundle for data transmission according to the fifth aspect, the outer periphery of the signal line bundle for data transmission having the above-described structure is formed on the outer periphery of a ferromagnetic metal layer having a relatively high resistivity. Since it is covered with a shield layer made of a horizontal winding or braid of a magnetic conductive wire, the data transmission signal wire bundle on the inner peripheral side of the shield layer is shielded at a high frequency when viewed from the outside,
Radiation of high-frequency electromagnetic waves and pickup of high-frequency noise can be reduced.

According to a sixth aspect of the present invention, there is provided a data transmission cable characterized in that the data transmission signal line bundles having the above-described configurations are individually or mixed and bundled or twisted. In the data transmission cable according to the sixth aspect, a plurality of data transmission signal wire bundles having the above-described configuration are bundled or twisted into a multi-core structure, so that transmission of high-frequency noise components is sufficiently suppressed while parallel data transmission is performed. And can suitably cope with speeding up of data transmission.

According to a seventh aspect of the present invention, there is provided a data transmission system characterized in that a data transmission signal line having the above configuration is provided with a shield layer made of a horizontal winding or braid around the data transmission signal line. Provide a transmission cable. In the data transmission cable according to the seventh aspect, the outer periphery of the data transmission cable having the above configuration is covered with a shield layer made of a non-magnetic conductor plated with a ferromagnetic metal in a horizontal winding or braid. The data transmission cable on the inner peripheral side can be shielded at a high frequency when viewed from the outside, so that the radiation of high-frequency electromagnetic waves and the pickup of high-frequency noise can be reduced. In particular, when the data transmission signal line bundle according to the fifth aspect is used, the data transmission signal line is shielded by the double shield layer, so that radiation of high-frequency electromagnetic waves and pick-up of high-frequency noise are reduced. It can be further reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this.

First Embodiment FIG. 1 is a sectional view showing the structure of a data transmission signal line according to a first embodiment of the present invention. The data transmission signal line 100 is a nonmagnetic signal conductor 1 having a relatively low resistivity.
A ferromagnetic metal plating layer 2 having a relatively high resistivity
Is formed. The material of the nonmagnetic signal conductor 1 is, for example, copper (resistivity at room temperature = 1.72 μΩ · cm).
Degree). The material of the ferromagnetic metal plating layer 2 is, for example, pure iron (resistivity at room temperature = 10.0 μΩ · cm). Instead of pure iron, iron oxide, nickel, cobalt, chromium, or an alloy containing them may be used. The diameter φ of the nonmagnetic signal conductor 1 is, for example,
0.127 mm. The thickness τ of the ferromagnetic metal plating layer 2 is, for example, 0.5 to 2.5 μm. According to the above-described data transmission signal line 100, a noise filter characteristic for attenuating high-frequency noise components can be obtained, so that transmission of high-frequency noise components (for example, about 200 MHz or more) can be sufficiently suppressed, and data transmission errors can be reduced. Can be done.

-Second Embodiment- FIG. 2 is a sectional view showing the structure of a data transmission signal line according to a second embodiment of the present invention. The data transmission signal line 200 is a nonmagnetic signal conductor 1 having a relatively low resistivity.
Has a composite structure in which a pure iron plating layer 2a is formed on the outer periphery and a nickel plating layer 2b is formed on the outer periphery by flash plating.

According to the data transmission signal line 200 described above, since the pure iron plating layer 2a is protected by the nickel plating layer 2b, the pure iron plating layer 2a is hardly rusted, and the deterioration with time of the characteristics can be reduced. .

Third Embodiment FIG. 3 is a sectional view showing the structure of a data transmission signal bundle according to a third embodiment of the present invention. The data transmission signal line bundle 300 is the data transmission signal line 100 shown in FIG.
(A ferromagnetic metal plating layer 2 having a relatively high resistivity is formed on the outer periphery of the non-magnetic signal conductor 1 having a relatively low resistivity). 3 is formed. According to the above-described data transmission signal line bundle 300, a plurality of the data transmission signal lines 100 are bundled or twisted into a collective line or a stranded line, so that the transmission loss for the data signal is further reduced and the high frequency noise component is reduced. The noise filter characteristics to be attenuated can be improved.

Fourth Embodiment FIG. 4 is a sectional view showing the structure of a data transmission signal bundle according to a fourth embodiment of the present invention. The data transmission signal bundle 400 is the data transmission signal bundle 300 of FIG.
This is a configuration in which a shield layer 41 is formed on the outer periphery of (a plurality of data transmission signal lines 100 of FIG. 1 are bundled or twisted and the insulating layer 3 is formed on the outer periphery thereof). The shield layer 41 includes a ferromagnetic metal plating layer having a relatively high resistivity (eg, a pure iron layer) on the outer periphery of a non-magnetic conductive wire having a relatively low resistivity (eg, a copper wire; equivalent to 1 in FIG. 1). 1 (corresponding to 2 in FIG. 1) (the signal line 100 for data transmission in FIG. 1).
(Same configuration as that of the above). According to the above-described data transmission signal bundle 400, the data transmission signal bundle 3
00 is covered with a shield layer 41 formed of a horizontal winding or braid of a non-magnetic conductive wire plated with a ferromagnetic metal, so that the data transmission signal wire bundle 300 is shielded at a high frequency when viewed from the outside, and The radiation of electromagnetic waves and the pick-up of high-frequency noise can be reduced.

Fifth Embodiment FIG. 5 is a sectional view showing the structure of a data transmission cable according to a fifth embodiment of the present invention. The data transmission cable 500 is the data transmission signal line bundle 400 shown in FIG.
In this configuration, a plurality of (the shield layer 41 is formed on the outer periphery of the data transmission signal line bundle 300 in FIG. 3) is bundled or twisted, and the insulating layer 51 is formed on the outer periphery. According to the above data transmission cable 500, a plurality of data transmission signal wire bundles 400 are bundled or twisted to form a multi-core structure, so that parallel data transmission can be performed while sufficiently suppressing transmission of high frequency noise components. Therefore, it is possible to suitably cope with high-speed data transmission.

Sixth Embodiment FIG. 6 is a sectional view showing the structure of a data transmission cable according to a sixth embodiment of the present invention. The data transmission cable 600 is the same as the data transmission cable 500 shown in FIG.
(A plurality of data transmission signal wire bundles 400 of FIG. 4 are bundled or twisted, and an insulating layer 51 is formed on the outer periphery thereof)
Is a configuration in which a shield layer 61 is formed on the outer periphery of the device. The shield layer 61 has a relatively high resistivity ferromagnetic metal plating layer (eg, a pure iron layer) on the outer periphery of a non-magnetic conductive wire (eg, a copper wire; equivalent to 1 in FIG. 1) having a relatively low resistivity. 1 (corresponding to 2 in FIG. 1) (the signal line 10 for data transmission in FIG. 1).
0). According to the above-described data transmission cable 600, the outer periphery of the data transmission cable 500 is covered with the shield layer 61 made of a non-magnetic conductive wire plated with a ferromagnetic metal in a horizontal winding or braid. The wire bundle 400 is shielded at a high frequency when viewed from the outside (the signal wire bundle 300 for data transmission is double-shielded by the shield layers 41 and 51) to further reduce the radiation of high-frequency electromagnetic waves and the pickup of high-frequency noise. I can do it.

Seventh Embodiment FIG. 7 is a sectional view showing the structure of a SCSI cable 700 according to a seventh embodiment of the present invention. Generally, SCS
The number of signal lines of the I cable is 25 pairs (50 lines). As shown in FIG. 7A, this SCSI cable 700
Are the arrangement positions (indicated by dotted lines) A1 and B of the data signal path.
, B24, a nonwoven fabric tape 90 is spirally wound around the outer periphery, an aluminum polyester tape 91 is spirally wound around the outer periphery thereof, and the outer periphery is covered with a braid 92 of a tin-plated copper wire. Insulation sheath 9 on outer periphery
3 is formed. The tin-plated copper wire is obtained, for example, by applying tin plating to the outer periphery of a copper wire having a strand diameter of 0.1 mm. As shown in FIG. 7B, the data transmission signal bundle 300 is located at the arrangement positions A1, B1 to B24.
A, 300B is twisted pair twisted data transmission signal wire bundle is arranged. The data transmission signal line bundle 300
The configurations of A and 300B are the same as those of the data transmission signal bundle 300 (see FIG. 3) according to the third embodiment.
In other words, as shown in FIG. 7C, the data transmission signal wire bundle 300A (the same configuration as 300B) has a relatively low resistivity non-magnetic signal conducting wire 1 The configuration is such that only seven data transmission signal lines 100 (see FIG. 1) on which the high ferromagnetic metal plating layer 2 is formed are bundled or twisted, and an insulating layer 3 is formed on the outer periphery thereof.
The nonmagnetic signal conductor 1 has, for example, a diameter φ = 0.127 m.
m copper wire. The ferromagnetic metal plating layer 2 is, for example, pure iron having a thickness τ = 0.5 to 2.5 μm.

FIG. 8 is a block diagram showing an attenuation characteristic measuring system SG for measuring the attenuation characteristic of the SCSI cable 700. This attenuation characteristic measuring system SG
The arrangement position of the measurement target of the CSI cable 700 (for example, B
12) Data transmission signal bundles 300A, 300B
BALance to UNb
alance transformer) connected to a network analyzer A via TR1 and TR2. Note that the data transmission signal wire bundle 300 outside the measurement target (other than B12)
A and 300B were open at one end and all the other ends were short-circuited to the braid 92 of the tin-plated conductive wire. Note that a gain / phase analyzer may be used instead of the network analyzer A.

FIGS. 9 to 11 are graphs showing measurement results obtained by the attenuation characteristic measuring system SG shown in FIG. Note that S
The cable length of the CSI cable 700 is 2 m. S
The characteristics of the CSI cable 700 are shown by solid lines. As a first comparative example, a conventional SCSI cable 90
The characteristic relating to 0 (see FIG. 16) is indicated by a dotted line. As a second comparative example, an SCS equipped with an LC filter circuit 901
The characteristics of the I cable 900 (see FIG. 18) are indicated by a dashed line. FIG. 9 shows the measurement results for the thickness τ = 0.5 μm of the ferromagnetic metal plating layer 2 (see FIG. 7). From the graph, it can be seen that the attenuation at the frequency f of about 100 MHz or more is larger than that of the first comparative example. Also, it can be seen that the attenuation at or above the frequency f = 350 MHz is greater than in the second comparative example. By the way, f = 500M
The amount of attenuation at Hz is about 14 dB (about 6 dB larger than the first comparative example and about 9 dB larger than the second comparative example). FIG. 10 shows the measurement results for the thickness τ = 1.0 μm. From the graph, it can be seen that the attenuation when the frequency f is about 100 MHz or more is even greater than when τ = 0.5 μm. Incidentally, the attenuation at f = 500 MHz is about 21 dB (1 according to the first comparative example).
(About 3 dB larger than the second comparative example, about 16 dB). FIG. 11 shows the measurement results for the thickness τ = 1.5 μm. From the graph, it can be seen that the attenuation when the frequency f is about 100 MHz or more is even greater than when τ = 1.0 μm. Incidentally, the attenuation at f = 500 MHz is about 29 dB (21 d from the first comparative example).
B and about 24 dB larger than the second comparative example). According to the SCSI specification, the frequency of the data signal is at most about several tens of MHz. Therefore, FIGS.
In any of the above characteristics, the attenuation is sufficiently small for the data signal. On the other hand, for a high frequency of about 200 MHz or more, the attenuation becomes large.

FIG. 12 is an explanatory diagram showing a SCSI connection system using the SCSI cable 700. In the SCSI connection system C, the SCS of the personal computer P
The SCSI cable 7 is connected to the I interface port.
00, a hard disk device HD is connected. Note that another hard disk device, an MO (Magnetic Optical) disk device, or a CD-ROM (Compact Disk Read Only M
emory) or a SCSI-compliant device such as a scanner device may be further connected. As described above with reference to FIGS. 9 to 11, in this SCSI cable 700,
Since there is a large amount of attenuation with respect to a high frequency of about 200 MHz or more, it is not necessary to mount a high frequency countermeasure component such as a ferrite core.

According to the above SCSI cable 700,
Since the data transmission signal line 100 in which the ferromagnetic metal plating layer 2 is formed on the outer periphery of the nonmagnetic signal conductor 1 is used,
Transmission of high-frequency noise components of about MHz or higher can be sufficiently suppressed, and data transmission errors can be reduced. Therefore, it is not necessary to mount a high-frequency countermeasure component, and the cost can be reduced, and the appearance of the cable wire can be maintained.

Eighth Embodiment FIG. 13 is a sectional view showing the structure of a SCSI cable 800 according to an eighth embodiment of the present invention. As shown in FIG. 13A, this SCSI cable 800
Each arrangement position (shown by a dotted line) A1, B1,
A nonwoven fabric tape 90 is spirally wound around the outer periphery of B2,..., B24, an aluminum polyester tape 91 is spirally wound around the outer periphery, the outer periphery is covered with a shield layer 81, and an insulating sheath 93 is wound around the outer periphery. It is a formed configuration. The shield layer 81 is formed of a ferromagnetic metal plating layer having a relatively high resistivity (for example, a pure iron layer) on the outer periphery of a non-magnetic conductive wire having a relatively low resistivity (for example, a copper wire; equivalent to 1 in FIG. 1). 1 (corresponding to 2 in FIG. 1) (same configuration as the data transmission signal line 100 in FIG. 1). As shown in FIG. 13B, the arrangement position A
1, B1 to B24 include a signal line bundle 300 for data transmission.
A, 300B is twisted pair twisted data transmission signal wire bundle is arranged. The data transmission signal line bundle 300
The configurations of A and 300B are the same as those of the data transmission signal bundle 300 (see FIG. 3) according to the third embodiment.
That is, as shown in FIG. 13 (c), the data transmission signal wire bundle 300A (300B also has the same configuration) is provided around the outer periphery of the non-magnetic signal conductor 1 having a relatively low resistivity. The configuration is such that only seven data transmission signal lines 100 (see FIG. 1) on which the high ferromagnetic metal plating layer 2 is formed are bundled or twisted, and an insulating layer 3 is formed on the outer periphery thereof.

According to the above SCSI cable 800,
Since the outer peripheral side of the cable is covered with the shield layer 81 composed of a horizontal winding or braid of a non-magnetic conductive wire plated with a ferromagnetic metal, radiation of high-frequency electromagnetic waves and pick-up of high-frequency noise can be reduced.

[0032]

According to the signal line for data transmission, the signal line bundle for data transmission and the cable for data transmission of the present invention, the signal line, the signal line bundle and the cable itself can be provided with a filter characteristic for attenuating high frequencies. Transmission stability and reliability can be improved. In addition, since the ferromagnetic metal layer formed on the outer periphery of the non-magnetic signal conductor has a high-frequency shielding ability, it reduces radiation of high-frequency electromagnetic waves and pick-up of high-frequency noise, and the Voluntary Control Council for Interference from Information Processing Equipment ( VCCI; Voluntary Control Council for Interference
data processing equipment and electronic office ma
chines) can be easily regulated. In addition, since high-frequency countermeasure components such as a ferrite core can be eliminated, costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a data transmission signal line according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a data transmission signal line according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a data transmission signal bundle according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a data transmission signal bundle according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a data transmission cable according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a data transmission cable according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view showing a SCSI cable according to a seventh embodiment of the present invention.

8 is a configuration diagram illustrating an attenuation characteristic measuring system for measuring the attenuation characteristic of the SCSI cable of FIG. 7;

FIG. 9 is a graph showing measurement results obtained by the attenuation characteristic measurement system of FIG.

FIG. 10 is another graph showing a measurement result obtained by the attenuation characteristic measurement system of FIG.

FIG. 11 is still another graph of the measurement result obtained by the attenuation characteristic measuring system of FIG.

FIG. 12 is an explanatory diagram of a SCSI connection system using the SCSI cable of FIG. 7;

FIG. 13 is a sectional view showing a SCSI cable according to an eighth embodiment of the present invention.

FIG. 14 is an explanatory diagram showing an example of a conventional SCSI connection system using a SCSI cable.

FIG. 15 is a cross-sectional view showing a structural example of a conventional SCSI cable.

16 is a graph showing attenuation characteristics of the SCSI cable of FIG.

FIG. 17 shows a SCSI using the SCSI cable shown in FIG.
It is explanatory drawing which shows the other example of a connection system.

FIG. 18 is a graph showing attenuation characteristics of a SCSI cable equipped with an LC filter circuit.

[Explanation of symbols]

100, 200 Data transmission signal line 300, 300A, 300B 400 Data transmission signal line bundle 500, 600 Data transmission cable 700, 800 SCSI cable 1 Non-magnetic signal conductor 2 Ferromagnetic metal plating layer 2a Pure iron plating layer 2b Nickel plating Layer 3, 51 Insulating layer 41, 61, 81 Shielding layer 92 Braiding of tinned copper wire 93 Insulating sheath

Claims (7)

[Claims] 1. A data transmission signal line, wherein a ferromagnetic metal layer having a relatively high resistivity is formed on the outer periphery of a nonmagnetic signal conductor having a relatively low resistivity. 2. The data transmission signal line according to claim 1, wherein the ferromagnetic metal layer is made of pure iron, iron oxide, nickel, cobalt, chromium, an alloy containing at least one of these materials, and a material of the material. A signal line for data transmission, which is formed of any one of a composite structure in which a plurality of composites are combined. 3. The data transmission signal line according to claim 1, wherein said ferromagnetic metal layer has a thickness of:
A signal line for data transmission, which is 0.5 to 2.5 μm. 4. A plurality of signal lines for data transmission according to claim 1 bundled or twisted,
A signal line bundle for data transmission, wherein an insulating layer is formed on an outer periphery thereof. 5. A shield layer comprising a data transmission signal line bundle according to any one of claims 1 to 3, wherein the shield layer comprises a horizontal winding or a braid around the insulating layer of the data transmission signal line bundle according to claim 4. A signal line bundle for data transmission, characterized by forming: 6. A data transmission cable characterized in that the data transmission signal line bundles according to claim 4 or 5 are individually or mixed and bundled or twisted. 7. A data transmission cable according to claim 6, wherein a shield layer made of a horizontal winding or braid of the data transmission signal line according to any one of claims 1 to 3 is formed on an outer periphery of the cable. Cable for data transmission characterized by the following.