JP2001266659A - Transmission cable and apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission cable for assuring a transmission signal quality level which is highly flexible for arrangement inside a casing. SOLUTION: In a cable for transmitting an electric power and a signal, the cable has an incoming- and outgoing-noise control means. The incoming- and outgoing-noise control means is a flexible noise control part and disposal around the cable. The flexible noise control part is a conductive-sheet or knitted shield material wherein a thickness of the conductive sheet and a diameter of a knitted wire are configured to be more than a superficial skin depth of a frequency to be countermeasured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a cable for transmitting power and signals between a plurality of circuit boards disposed inside a housing, and to a transmission cable for ensuring the quality of a transmission signal. The present invention relates to means for suppressing the incidence and emission of noise.

[0002]

2. Description of the Related Art Recent advances in digital equipment and the rapid spread of mobile phones have led to advances in information and communication technologies, higher frequencies in computer CPUs, higher data transmission rates between circuit boards, and high-speed wireless communications. With the spread of LAN,
Problems caused by electromagnetic waves generated from these devices include electromagnetic interference such as mutual interference and malfunction of the devices. In particular, in electronic devices having a circuit board such as a computer, serious problems such as malfunction of the device have become apparent. Generally, in a computer or the like, a plurality of circuit boards provided inside the housing are connected by cables to transmit power and signals. In the transmission of power and signals by a cable connecting between circuit boards, when a plurality of circuit boards are connected to different frame grounds, the ground potential of the frame ground is often different. This ground potential is called a common mode potential. If a cable is used to connect between circuit boards connected to the frame grounds having different ground potentials, the common mode current due to this common mode potential flows intensively in the cable, and common mode noise is radiated from the cable. There are drawbacks.
Further, even when the circuit board is connected to the frame ground of the common casing, a current loop is formed by a signal current formed by the cable, the board, and the casing, and a feedback current thereof. Differential mode noise is emitted. As a countermeasure against these radiated noises, there is a case where one ferrite core is arranged around a flat cable which is a bus line having a high transfer speed, but in reality, almost no countermeasure is taken. This is because the casing of an electronic device such as a computer is usually provided with an electromagnetic wave shield by coating with a metal or applying a conductive paint. This electromagnetic wave shield suppresses electromagnetic wave noise from entering the inside of the housing and radiating to the outside due to reflection. Therefore,
As described above, the radiation noise from the cable inside the housing is repeatedly reflected inside and is not radiated to the outside, so that the noise does not directly propagate to other devices.
In other words, such electronic devices do not pose a problem in the noise standards established in each country, and are widely spread as products with noise countermeasures. Therefore, radiation to the outside
As a method of suppressing the transmitted noise, the cable itself that connects the personal computer and the digital device, and the board itself at the entrance and exit of the cable are provided with noise countermeasures. The fact is that it is hardly applied. As a result, electromagnetic noises of various frequencies exist in the housing of the personal computer. Therefore, as the speed of the CPU and the speed of the data line of the bus advance, the noise incident on the cable at a level which has not been a problem has been a new problem. This is a problem in that electromagnetic wave noise that has been repeatedly reflected inside the housing is guided to the cable and is output as electrical noise to the circuit board to which the cable is connected, resulting in malfunction of the device itself. As a countermeasure against such incident noise, there is a method of improving crosstalk by inserting a GND line between signal lines of a flat cable which is a data line of a bus. However, there is actually no effect depending on how the cables are routed, and it is not sufficient as a measure against incident noise. Particularly, in the case where the transfer speed is high like ATA-66 and data is transferred at both rising and falling edges of the strobe signal,
There is a problem that even if a slight noise enters at the time of rising or falling, a malfunction is likely to occur. Such problems will increase more and more with the increase in the speed of the CPU and the transfer speed of the transmission cable in the future.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cable for transmitting a signal between a plurality of circuit boards disposed inside a housing, and to make noise incident on the transmission cable. And by suppressing radiation, to ensure the quality of the transmission signal, and to provide a flexible transmission cable for arranging inside the housing, and to provide a device using the transmission cable. is there.

[0004]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have conceived of a transmission cable having a remarkably improved configuration. That is, the first invention of the present application relates to a cable for transmitting electric power and a signal, wherein the cable has a means for suppressing noise incidence and radiation, and the means for suppressing noise incidence and radiation has flexibility. It is a suppression part and is arranged around the cable,
The flexible noise suppression component is a conductive thin plate or a knitted shield material, and the thickness of the conductive thin plate, the knitted wire diameter is equal to or greater than the skin depth of a frequency to be treated. A transmission cable characterized in that the transmission cable is made of a shielding material. In the second invention of the present application, wherein the thin plate is in a state of foil, band, tape, sheet, or the like, the first invention is characterized in that the shield material is made of a magnetic material. It is a transmission cable according to the invention. According to a third aspect of the present invention, there is provided a cable for transmitting power / signal, wherein the cable has means for suppressing noise incidence and radiation, and the means for suppressing noise incidence and radiation has flexibility in noise suppression. The flexible noise suppression component is disposed around a cable, and the flexible noise suppression component is formed by dispersing at least one material of magnetic powder and conductive fiber in a resin. The transmission cable according to the first invention, characterized in that the transmission cable is a radio wave absorber. According to a fourth aspect of the present invention, there is provided a cable for transmitting a power or a signal, the cable having a radiation noise suppressing means, wherein the radiation noise suppressing means is a ferrite core, and the ferrite cores are different by at least two or more. A transmission cable characterized in that the transmission cable is provided in combination with those having the following characteristics. According to a fifth aspect of the present invention, there is provided a cable for transmitting power and a signal, the cable having a means for suppressing the incidence and emission of noise, and the means for suppressing the incidence and emission of noise is provided by the first to fourth aspects of the present invention. A transmission cable characterized by taking measures against noise by combining two or more of these methods. A sixth invention of the present application is a transmission cable, wherein the transmission cable according to any one of the first to fifth aspects of the present invention is a flat cable. A seventh invention of the present application is an apparatus, wherein the transmission cable according to any one of the first to sixth inventions is disposed inside a housing.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The transmission cable according to the present invention is a cable configured so that the cable does not impede the flexibility of the cable because the cable is disposed inside the housing. It is a transmission cable characterized by being arranged around. Here, one of the noise problems that the present inventors have focused on is that when a plurality of circuit boards provided inside the housing are connected by a cable to transmit power / signal, the plurality of circuit boards may be different. When connected to a frame ground, the common mode current caused by the common mode potential concentrates in the cable and common mode noise is radiated from the cable. Even when connected to the frame ground, a current loop is formed by the signal current and the feedback current formed by the cable, the board, and the housing, and the noise problem that the differential mode noise is radiated by the current loop. These are all radiation noise from the cable. Another noise problem is that not only the noise radiated from the cable, but also the electromagnetic waves radiated from other cables, boards, ICs, etc., are repeatedly reflected inside the housing, and are induced into the cable as electromagnetic wave noise, which causes electrical noise. Noise is output to a circuit board to which the cable is connected as noise, and the device malfunctions. This problem is caused by noise incident on the cable. Less than,
Embodiments of the present invention will be described, and features thereof will be described in detail.

(Embodiment 1) FIG. 1 shows an example of this embodiment. The structure of this embodiment is such that a 35 μm copper foil 3 is wound around a cable provided with an insulating layer 2 made of PVC around a wire core 1, and furthermore, an outer layer which is an insulating layer formed of PVC around the circumference. 4 are formed. The first purpose of this configuration is to produce a flexible transmission cable to be disposed inside the housing. The second purpose of this configuration is to improve the radiation noise problem of the cable provided inside the housing. This is because, in this transmission cable configuration, when an electric signal flows through the wire core 1, magnetic flux is generated,
A back electromotive force is generated in the copper foil 3 by the magnetic flux, and the function of suppressing radiation noise is achieved by using the generation of the magnetic flux by the back electromotive force to cancel the magnetic flux radiated from the cable. . Further, when shielding is performed by a conductor such as a copper foil 3, a current generated by the back electromotive force flows on the surface of the conductor. Therefore, by connecting the copper foil 3 to the ground, the electrostatic shielding effect is also used. still,
The current flowing on the surface of the conductor is determined by the skin depth, and the skin depth becomes shallower as the frequency increases. FIG. 11 shows the shielding effect of the copper foil 3 used in the above embodiment in the presence or absence of the ground.
FIG. 12 shows the relationship between the skin depth of copper and the frequency characteristics. As can be seen from this figure, when the cable is shielded using the copper foil 3, the shielding effect is 20 dB or more at 1 MHz to 1 GHz. Further, by connecting the copper foil 3 to the ground, an electrostatic shielding effect is exhibited, so that the shielding effect increases as the frequency increases. This is because the frequency of the skin depth, which is the same thickness as that of the copper foil 3 of 35 μm, is about 3.5 MHz.
This is a result of utilizing the property of allowing a current to flow efficiently within the thickness of the copper foil 3. Therefore, when shielding noise with a conductor, use a conductive thin plate with a thickness equal to or greater than the skin depth at the frequency you want to take measures against, and connect the conductive thin plate to the ground to provide magnetic shielding and static shielding. Electromagnetic waves can be efficiently suppressed by both of the electric seals. More preferably, it is desirable to use a conductive thin plate that is at least twice the skin depth. In this embodiment, a copper foil is used for the conductive thin plate. However, there is no problem even if a metal such as an aluminum foil is used, as long as it has conductivity. In consideration of the skin depth in the frequency band where it is desired to take measures with a shielding material made of a conductive thin plate, it is preferable to use silver or copper having high conductivity. It is desirable to use inexpensive aluminum with a high rate. The third purpose of this configuration is not only to improve the noise radiated from the cable, but also to induce electromagnetic waves radiated from other cables, substrates, ICs, etc., and to enter the cable as electrical noise. The problem of noise to be generated is also improved by the above-described shielding effect.

(Embodiment 2) In this embodiment, instead of the 35 μm copper foil described in FIG. 1 of Embodiment 1, the relative magnetic permeability is 8000 (at 100 KHz) and the specific resistance is 1.3 × 10 5 ^-6
20μm formed from Ωm Co-based amorphous alloy
The configuration is exactly the same except that a thin plate is used. In addition, although the amorphous alloy is usually annealed to improve the relative magnetic permeability, the annealing causes the embrittlement. When a cable is manufactured using this embrittled amorphous alloy or when the cable is used, there is a problem that the amorphous alloy is cracked and the noise suppressing effect is hindered.
Therefore, in the present case, a flexible transmission cable was produced by winding the cable without annealing. The purpose of this configuration is, as described above, to produce a transmission cable that is highly flexible to be arranged inside the housing, and to solve the problem of radiation noise of the cable provided inside the housing and the incidence on the cable. It is to improve the noise problem. The feature of this configuration is that a conductor having magnetic properties is used for the shield material. This is based on the fact that when a conductor having magnetic properties such as a Co-based amorphous alloy is used, the effect of canceling out magnetic flux due to the back electromotive force generated in the shielding material is improved in proportion to the relative magnetic permeability of the material. is there. FIG. 13 shows the result of comparing the shielding effect of the shielding material used in Example 2 with the copper foil used in Example 1. FIG. 14 shows the frequency characteristics of the relative magnetic permeability, and FIG. 15 shows the relationship between the skin depth and the frequency. Although a Co-based amorphous alloy is used in this embodiment, a similar effect can be obtained with a conductor having magnetic properties such as an Fe-based amorphous alloy, pure iron, and a permalloy alloy. However, the relative permeability of a permalloy alloy is extremely deteriorated due to strain, and is not suitable for a transmission cable disposed inside a housing. Therefore, it is preferable to use an amorphous alloy in consideration of the flexibility, the magnitude of the relative magnetic permeability, the skin depth in a frequency band to be treated by the shield material, and the like. As for the shielding method of the first and second embodiments, only a method of winding a thin tape or a sheet-like material around a cable has been described.
It is not limited only to this mode. For example, a knitted shielding material 3a may be used instead of a thin plate as shown in FIG. 2, or a shielding material 6 may be provided between an insulating layer formed of a resin film 5 and an adhesive tape 7 as shown in FIG. A structure in which the sandwiched shielding material 3b is wound around a cable as shown in FIG. 4 may be used. When winding the shield material around the cable, it is important not to leave a gap in the shield, and the method of fixing to the cable is not particularly limited as long as it does not hinder the flexibility of the transmission cable. . Of course, the same applies when the cable is shielded with a knitted shield material. In addition, the coverage at the time of shielding the cable is preferably 65% or more, and more preferably 85% or more. Although PVC is used as the insulating layer of the cable, any material can be used for forming the insulating layer, as long as it can provide flexibility, and is preferably formed of a flame-retardant resin. . This is the same for the resin film 5.

(Embodiment 3) As shown in FIG. 4, a cable in which an insulating layer 2 made of PVC is provided around a wire core 1 as shown in FIG. Body 3c
Is wound and fixed. In addition, although the fixing method was performed using an adhesive tape, it is not particularly limited as long as it can be fixed around the cable. FIG. 5 shows an example of the radio wave absorber 3c in this embodiment.
This radio wave absorber 3c is obtained by dispersing carbon fiber having a fiber length of about 2 mm in chloroprene rubber by 40% by weight,
The electromagnetic wave reflection layer 8 formed into a sheet having a thickness of m was formed. Next, a flat powder of a nanocrystallized alloy made of Fe—Cu—Nb—Si—B is dispersed in chloroprene rubber by 73% by weight to form an electromagnetic wave absorbing layer 9 sheeted to a thickness of 0.5 mm. did. Next, 82% by weight of a granular powder of a nanocrystallized alloy composed of Fe-Cu-Nb-Si-B was dispersed in chloroprene rubber to form an electromagnetic wave absorbing layer 10 having a sheet thickness of 0.5 mm. Formed. Next, 70% by weight of the carbonyl iron alloy granular powder was dispersed in chloroprene rubber, and the electromagnetic wave absorbing layer 1 was formed into a sheet having a thickness of 0.4 mm.
1 was formed. These four types of sheets were sequentially laminated and integrated to form a sheet-like radio wave absorber 3c having a total thickness of 1.8 mm. FIG. 16 shows the electromagnetic wave noise absorptivity of the radio wave absorber manufactured in this example.
From this figure, it can be seen that this radio wave absorber has a high absorption rate of 70% or more in a wide frequency band of 0.5 to 10 GHz. When this radio wave absorber is used for the transmission cable, if the radiation noise of the cable becomes a problem, it is preferable to arrange the electromagnetic wave absorbing layer 11 side so as to be in close contact with the cable. It is effective to dispose the noise radiated near the connector, and more desirably, to dispose it over the entire cable.
Also, if the noise radiated from other cables, boards, ICs, etc. is incident on the cable,
It is desirable to arrange the electromagnetic wave reflection layer 8 side so as to be in close contact with the cable, and when it is possible to identify the location where the noise is incident, it is effective to arrange it at least at that location. good. Further, in order to suppress the incidence and radiation of noise more efficiently, as shown in FIG.
In this case, it is not necessary to use the same electromagnetic wave absorbing layers 12a and 12b on both sides, and it is desirable to select the optimum electromagnetic wave absorbing layer for the electromagnetic wave noise to be reduced. . The feature of this embodiment is that the electromagnetic wave noise radiated from the cable and the electromagnetic wave incident on the cable are determined by the complex magnetic permeability (μ′−μ ″) and the complex permittivity (ε′−ε ″) of the electromagnetic wave absorbing layers 9, 10 and 11. It converts noise into thermal energy and absorbs it. The reason why the three different electromagnetic wave absorbing layers 9, 10, 11 are used is to absorb electromagnetic waves in a wide band by combining different electromagnetic wave absorbing performances in frequency bands. Therefore, when the frequency band to be addressed is a narrow band, there is no problem even if a radio wave absorber composed of only one electromagnetic wave absorbing layer adapted to the frequency band is used. Further, in the broadband type radio wave absorber, it is desirable to stack a plurality of electromagnetic wave absorbing layers in order of decreasing impedance matching frequency. still,
The magnetic material used for the electromagnetic wave absorbing layer is not limited to the magnetic materials described in the examples, but may be, for example, a metal magnetic powder such as an amorphous alloy or permalloy. It is desirable that it is given. The magnetic material is not limited to the metal magnetic powder alone, but may be a ferrite powder or any magnetic powder. In order to absorb electromagnetic wave noise in an arbitrary frequency band, the spatial impedance and the impedance of the radio wave absorber may be matched by appropriately adjusting the selection of the magnetic material, the mixing amount of the magnetic powder and the resin, and the thickness of the sheet. For example, at 1 GHz, the characteristics of the electromagnetic wave absorbing layer are preferably μ ′ ≧ 5, μ ″ ≧ 3, ε ′ ≧ 20, and ε ″ ≧ 0.5, and at 5 GHz, μ ′ ≧ 0.5. ≧ 1.2, μ ″ ≧ 0.5, ε ′ ≧ 5, and ε ″ ≧ 0.1. In this embodiment, the electromagnetic wave reflection layer 8 is formed so that the electromagnetic wave absorption layers 9, 10, and 11 efficiently absorb the electromagnetic wave noise. This is because the electromagnetic wave noise incident from the electromagnetic wave absorbing layer 11 side is not reflected by the electromagnetic wave absorbing layers 9, 10 and 11, but is reflected by the electromagnetic wave reflecting layer 8. This is absorbed by the layers 9, 10, and 11. The conductive material dispersed in the electromagnetic wave reflecting layer 8 may be not only carbon fiber but also metal fiber. In order to efficiently reflect radio waves, it is desirable to set the sheet resistance to 100 KΩ or less.
This is because, when electromagnetic waves are incident on a resin in which a conductor such as carbon is dispersed in a resin, a high-frequency current is generated in the conductor, but the resin acts as a resistance to the high-frequency current and converts it into heat energy. There is work. For this reason, if the sheet resistance is high, it acts as a radio wave absorber and does not serve as a reflector. Thus, the conductive fiber can be used as an electromagnetic wave absorbing layer. In addition, the resin used when forming the flexible radio wave absorber was chloroprene, but may be a resin such as silicon rubber or butyl rubber, as long as it does not impair the flexibility of the cable. Any material may be used, but it is preferable to use a flame-retardant resin. The thickness of the radio wave absorber is preferably not more than 2.2 mm so as not to hinder the flexibility of the cable, and each layer is not less than 0.3 mm in order to effectively operate the electromagnetic wave reflection layer and the electromagnetic wave absorption layer. It is desirable to have a thickness of

(Embodiment 4) FIG. 7 shows an example of the configuration of this embodiment. The configuration of this embodiment is the same as that of the wire core 1
A ferrite core 13a having an initial magnetic permeability of 250 is arranged around a cable provided with an insulating layer 2 made of PVC around
Further, a ferrite core 1 having an initial magnetic permeability of 1000
4a. FIG. 17 shows impedance characteristics in this embodiment. From this result,
In this embodiment, the ferrite core 13a and the ferrite core 1
4A shows an impedance characteristic having both impedance characteristics. The feature of this embodiment is that electromagnetic wave noise radiated from the cable and electromagnetic wave noise incident on the cable are converted into thermal energy and absorbed by the complex magnetic permeability (μ′−μ ″) of the ferrite cores 13a and 14a. In addition, two different ferrite cores 13a, 14
The reason for using a is to absorb electromagnetic waves over a wide band by combining ferrite cores having different electromagnetic wave absorption performances in frequency bands. In other words, a cable that previously had only one type of ferrite core was able to suppress only the narrow-band radiation noise. By combining a plurality of different materials, the cable can suppress radiation noise over a wide bandwidth. is there. Therefore, the method of assembling ferrite cores is not limited to the method shown in this embodiment. For example, similar results can be obtained when cores are arranged and combined as shown in FIG. It should be noted that the material of the ferrite core is not limited to the materials described in the embodiments, but is desirably selected according to the frequency to be countermeasured, and the shape is the same. Further, in order to efficiently take measures against noise radiated by the cable as an antenna, it is desirable to arrange a ferrite core near the connector.

(Embodiment 5) As shown in FIG. 4, the configuration of this embodiment is a noise suppression component having flexibility in a cable provided with an insulating layer 2 formed of PVC around a wire core 1. 3
e is wound and fixed, and is an example of the transmission cable according to the fifth aspect. In addition, although the fixing method was performed using an adhesive tape, it is not particularly limited as long as it can be fixed around the cable. FIG. 9 shows an example of the noise suppression component 3e in this embodiment.
This noise suppression component 3e is composed of a 20 μm thick shield layer 17 formed of a Co-based amorphous alloy on a 75 μm polymer film 15 and a 60 μm adhesive layer 16.
Then, the shield layer 18 using a copper foil of 35 μm was attached with an adhesive layer 16 b of 60 μm to form a sheet-like noise suppression component 3 e having a total thickness of 250 μm. FIG. 18 shows the shielding effect of the magnetic field wave at 9 to 150 KHz of the noise suppressing component 3e manufactured in this embodiment. The purpose of this configuration is to produce a flexible transmission cable to be placed inside the housing, and to improve the radiation noise problem of the cable provided inside the housing and the incident noise to the cable. Among them, it is particularly effective in improving the noise problem from a low frequency band such as 10 KHz. The feature of this configuration is that a conductor having magnetic properties such as a Co-based amorphous alloy and a copper foil having good conductivity are used as the shield material. This is based on the fact that the shielding effect of a magnetic field at a low frequency is proportional to the relative magnetic permeability of the shielding material, and the effect of canceling out magnetic flux by back electromotive force generated in the shielding material is improved. In addition, by combining with a conductor having good conductivity, high frequency band noise is caused to flow to the ground, thereby providing an effect of electrostatic shielding. For this reason, the adhesive layer 16b in this embodiment is desirably an adhesive layer having conductivity. In addition, regarding the noise suppression effect in the high frequency band,
Embodiments 1 and 2 are individually described for each material, and therefore will not be described. In this embodiment, noise suppression was performed using a thin plate of a Co-based amorphous alloy and a copper foil. However, the contents described in claim 5 are not limited to this embodiment. The noise may be reduced by combining an absorber or a ferrite core and an amorphous alloy, and it is desirable to appropriately select and reduce the noise depending on the frequency band of the noise to be reduced and the type of noise. Note that these Examples 1
Each of the transmission cables described in (5) to (5) is a measure against noise with a single cable for simplicity of description, but a cable composed of a stranded cable or a plurality of cables may be simultaneously measured. The effect of can be obtained.

(Embodiment 6) In this embodiment, as shown in FIG. 10, a flexible noise suppression component 3e is wound around a flat cable 20 and fixed. It is an example of the described transmission cable.
In addition, the fixing method was performed using an adhesive tape,
There is no particular limitation as long as it can be fixed around the cable. Further, in this embodiment, the noise suppression component 3e is wrapped around the flat cable to take measures against noise. However, it is not always necessary to wrap the noise suppression component 3e, and the structure may be such that the flat cable is attached to both sides of the flat cable.
The characteristics of the noise suppression component 3e in this embodiment are as follows.
The description is omitted in the fifth embodiment. The purpose of this configuration is to produce a flexible transmission cable to be placed inside the housing, and to improve the radiation noise problem of the cable provided inside the housing and the incident noise to the cable. In particular, attention is focused on the fact that a transmission cable having a high transfer rate is a flat cable inside a housing, and the malfunction of the electronic device itself is improved by taking measures against noise in the flat cable. Therefore, the contents shown in claim 6 are not limited to this embodiment only.
Shielding materials, radio wave absorbers, and ferrite cores may be used for noise suppression only, or may be a combination of the above noise suppression components. It is desirable. In the first to sixth embodiments, a transmission cable having a wire core has been mainly described as a transmission cable disposed inside the housing. However, an effective method is also used for a transmission cable formed of a flexible substrate. Needless to say.

(Embodiment 7) In this embodiment, an ATA-66 cable provided inside a personal computer is subjected to noise suppression in the same manner as in Embodiment 6, and is an example as set forth in claim 7. In this embodiment, a transmission cable provided with noise suppression components for suppressing both radiated noise repeated inside the personal computer and incident noise induced in the cable due to the radiated noise is used, thereby improving the malfunction of the personal computer. be able to.

[0013]

As described above, according to the present invention,
In cables that transmit power and signals between a plurality of circuit boards installed inside the housing, noise and radiation to the transmission cable are suppressed to ensure the quality of the transmission signal, In addition, it is possible to provide a flexible transmission cable for arranging the transmission cables, and to provide an apparatus using the transmission cable.

[Brief description of the drawings]

FIG. 1 is a transmission cable according to an embodiment of the present invention.

FIG. 2 is a transmission cable according to another embodiment of the present invention.

FIG. 3 is a structure of a shield material according to an embodiment of the present invention.

FIG. 4 is a transmission cable according to another embodiment of the present invention.

FIG. 5 shows the structure of a radio wave absorber in one embodiment according to the present invention.

FIG. 6 shows the structure of a radio wave absorber according to another embodiment of the present invention.

FIG. 7 is a transmission cable according to another embodiment of the present invention.

FIG. 8 shows a transmission cable according to another embodiment of the present invention.

FIG. 9 shows the structure of a noise suppression component according to an embodiment of the present invention.

FIG. 10 shows a transmission cable according to another embodiment of the present invention.

FIG. 11 is a graph showing a shielding effect characteristic.

FIG. 12 is a graph showing the relationship between copper skin depth and frequency characteristics.

FIG. 13 is a graph showing a shielding effect characteristic.

FIG. 14 is a frequency characteristic diagram of relative magnetic permeability.

FIG. 15 is a diagram showing the relationship between skin depth and frequency.

FIG. 16 is a diagram showing the electromagnetic wave noise absorption rate of the radio wave absorber according to the present embodiment.

FIG. 17 is an impedance characteristic diagram according to the present embodiment.

FIG. 18 is a graph showing a shielding effect characteristic according to the present invention.

[Explanation of symbols]

 1: wire core 2: endothelial insulating layer 3, 3a, 3b, 3e, 6, 17, 18: shielding material 3c, 3d: radio wave absorber 4: outer insulating layer 5, 15: resin film 7, 16: adhesive tape 16a , 16b: adhesive layer 8, 8a: electromagnetic wave reflecting layer 9, 10, 11, 12a, 12b: electromagnetic wave absorbing layer 13a, 13b, 14a, 14b: ferrite core 20: flat cable

Continued on the front page F term (reference) 5G311 CA01 CE01 5G313 AB05 AC03 AD01 AD06 AE01 AE08 AE10 5G319 EA01 EA02 EB04 EB06 EC02 EC06 EC08 EC11 EC12 ED01 ED02 ED06

Claims (7)

[Claims] 1. A cable for transmitting power and signals, the cable having means for suppressing noise incidence and radiation, wherein the means for suppressing noise incidence and radiation is a flexible noise suppression component. The flexible noise suppression component is disposed around the cable, and the flexible noise suppressing component is a shielding material formed of a conductive thin plate or a knitted shape. A transmission cable characterized in that it is a shield material having a wire diameter of not less than a skin depth of a frequency to be countermeasured. 2. The transmission cable according to claim 1, wherein said shield member is made of a magnetic material. 3. A cable for transmitting power and signals, said cable having means for suppressing noise incidence and radiation, and said means for suppressing noise incidence and radiation is a flexible noise suppression component. The flexible noise suppressing component is disposed around a cable, and the flexible noise suppressing component is formed by dispersing at least one material of magnetic powder and conductive fiber in a resin. The transmission cable as described above, which is a radio wave absorber. 4. A cable for transmitting electric power and a signal, the cable having a means for suppressing radiation noise, wherein the means for suppressing radiation noise is a ferrite core, and the ferrite core has at least two different ferrite cores. A transmission cable characterized by being provided in combination with one having characteristics. 5. A cable for transmitting power and signals, the cable having means for suppressing noise incidence and radiation, wherein the means for suppressing noise incidence and radiation is used as claimed in claim 1. A transmission cable characterized in that a noise countermeasure is performed by combining two or more of these countermeasures. 6. The transmission cable according to claim 1, wherein the transmission cable is a flat cable. 7. An apparatus, wherein the transmission cable according to claim 1 is arranged inside a housing.