Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B11/00—Communication cables or conductors
  • H01B11/02—Cables with twisted pairs or quads
  • H01B11/12—Arrangements for exhibiting specific transmission characteristics
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
  • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
  • H01B7/2806—Protection against damage caused by corrosion

Definitions

• the present invention applies to the field of electroacoustics. It concerns the cables used for the transmission of audio signals between the electronic circuits processing or amplifying them in electroacoustic equipment, between these equipment themselves, as well as between these circuits or this equipment and the electroacoustic transducers (microphones or loudspeakers). speakers).
• the cables for the transmission of audio signals of an electrical nature provide the electrical connection between the electronic circuits processing or amplifying these signals, as well as between the sources of these signals (microphones, receiver of radio signals or players of recorded signals, for example) and these electronic circuits, as well as between these electronic circuits and the use of these signals (usually a speaker).
• modulation cables which transmit only a weak current and therefore very little energy
• power cables responsible for transmitting the electric power which will be transformed into another type of energy by a transducer (generally into sound energy in a loudspeaker).
• the present invention applies to modulation cables as well as to power cables.
• Litz wire wire made up of many very fine strands isolated and twisted together, making it possible to reduce the skin effect and improve the conductivity at frequencies ranging from a few tens to a few hundred kilo hertz - typically of 50 kHz to 500 kHz
• Litz wire wire made up of many very fine strands isolated and twisted together, making it possible to reduce the skin effect and improve the conductivity at frequencies ranging from a few tens to a few hundred kilo hertz - typically of 50 kHz to 500 kHz
• the basic idea of the invention is the identification of physical phenomena disturbing the transmission of the electrical signal. These phenomena correspond to the storage and the restitution of electric charges which distort the signal. These phenomena occur, on the one hand on the surface of the conductors and, on the other hand, in the materials used as insulators. They are linked to polarization phenomena occurring with dielectrics and induce memory phenomena in cables. These physical phenomena are not taken into account account by the usual theoretical models of cables and escape traditional measurements.
• the present invention thus relates to an electric cable for the transmission of audio signals, comprising one or more conductor (s) protected from the adsorption of molecules present in the air.
• these conductors are arranged in a tube made of a material having absorption properties.
• the conductors can be protected from adsorption, either by a surface treatment, or by being each surrounded by an insulator. They can also be made with an intrinsically poorly adsorbent material.
• these insulators are preferably chosen from insulators having weak and substantially linear memory characteristics.
• the conductor (s) are made with one or more enamelled copper wires.
• the absorbent tube is made with a plastic material loaded with conductive particles.
• the absorbent tube can be brought to a first predetermined potential.
• the absorbent tube is externally insulated by an insulating coating.
• This insulator is itself surrounded by a polarization shield which is preferably brought to a second predetermined potential.
• a method for producing a modulation cable according to the invention characterized in that at least two previously covered conductive wires are placed in an absorbent tube made of plastic material charged with conductive particles. each with a layer of hot-applied enamel.
• a shield made of braided conductive wire For a shielded version of this modulation cable, there is around the absorbing tube a shield made of braided conductive wire. This shielding can be isolated from the absorbent tube either by an insulating layer or by the use of individually insulated wires.
• a method is also proposed for producing a power cable according to the invention, characterized in that a conductive wire loaded with conductive particles is provided in several absorbent tubes made of conductive particles each previously covered with a layer of enamel deposited at hot and connected in parallel.
• These conductive wires are preferably previously arranged in the so-called Litz son configuration.
• FIG. 1 illustrates the traditional diagram of a capacitor having dielectric absorption
• - Figure 2 illustrates the constitution of a usual cable
• FIG. 5 illustrates the analysis of dielectrics involved in the stray capacitance of a cable
• FIG. 7 illustrates a first embodiment of a modulation cable according to the invention
• FIG. 8 illustrates another embodiment of a modulation cable according to the invention
• - Figure 9 illustrates a first embodiment of a power cable according to the invention
• FIG. 10 illustrates another embodiment of a power cable according to the invention.
• a first current corresponds to the charge of the theoretical capacitor, the insulator of which would be the dielectric. It corresponds to a stored and immediately available electrical charge. The corresponding energy is mainly stored and immediately recoverable;
• a second current corresponds to the dielectric absorption of the insulator. It corresponds to a stored electrical charge which can only be recovered after a significant time of up to several hours. The corresponding energy is mainly stored;
• a third current corresponds to the leakage current. There is no electrical charge stored and the corresponding energy is dissipated; - finally a fourth current corresponds to the breakdown of the materials beyond a value of the electric field as a function of time.
• FIG. 2 shows the classic construction of a single cable.
• the cable consists of a conductor 21 surrounded by an insulator 22 which electrically insulates the conductor and can have a mechanical holding role.
• the conductor 21 is generally made of metal (usually copper) and often has several strands to be flexible.
• the insulator 22 is made of flexible plastic material, the thickness of which is a function of the voltages present on the conductor.
• the main electrical quality sought for the conductor 21 is its low resistance; this is what leads to the choice of copper which, in addition to its interesting mechanical characteristics, has one of the lowest resistivities (around 21 10 ⁇ 6 ⁇ cm). It will be noted that the use of Litz wire corresponds to improving the conduction at certain frequencies. For insulator 22, the high value of the resistivity of common plastics (of the order of 10 14 , 10 16 ⁇ cm), makes this parameter not critical. How memory phenomena involved in this cable can be analyzed with the 'structure of Figure 3: the conductor 31 is within an insulating tube 32. This 32 is not usually insulator in close contact with the conductor 31.
• FIG. 5 shows the way in which the capacitors 44 and 46 are formed: the electrode 51 corresponds to the end of the cable, it is in close contact with a dielectric layer 53 corresponding to the non-conductive molecules present in the layer 34, at the conductor surface 31. Then we have an air layer 54 (33) and another dielectric 55 corresponding to the insulator 32 then an air layer 56 and the electrode 52 corresponds to the electrical environment. Parasitic capacity 47 can be analyzed in a similar way.
• the layer 53 To control the dielectrics which constitute the stray capacitances seen by the cable, it is necessary to prevent the layer 53 from forming either during the manufacture of the cable, or afterwards. It is also necessary to use an insulator with weak and linear memory characteristics. To prevent the layer 53 from forming, one can use as conductor or have on the surface of the conductor, a conductive material little inclined to adsorption. It is also possible to deposit on the surface of the conductor without adsorbed molecules an insulator having satisfactory dielectric absorption characteristics and providing around the conductor a sealed sheath which protects the latter from adsorption.
• a polarization conductor near or around the cable, which amounts to managing the potential of point 45 in FIG. 4.
• This conductor can have two negative effects: on the one hand it will increase the value of the stray capacitances 44 and 46 and will increase the field in the dielectrics, which will increase the effects of memory.
• a surface equipotential in the vicinity of the conductor it can cause the disappearance of continuous fields which polarized the dielectrics.
• this bias conductor it must be connected to a potential which is different from the mean value of the mean potential of the conductor 31.
• This potential is preferably chosen to be greater than ten to one hundred volts at the maximum value of the maximum potential of the conductor 31 or a value less than ten to one hundred volts than the maximum value of the minimum potential of the conductor 31.
• resistors 66 and 65 in the diagram of Figure 4 and obtain Figure 6.
• an absorbent medium around the insulator 32 This can be obtained by means of a tube disposed around the insulator, this tube being produced with a material of resistivity intermediate between that of the conductors and that of the insulators (of the order of 10 "1 , 10 +1 ⁇ cm).
• Such a material can advantageously be obtained with a conventional insulator loaded with conductive powder (in carbon for example) " .
• Audio connections generally include two conductors either to provide the reference ground of the signal or to ensure the return of the current supplied.
• the two conductors of the connection will advantageously be placed in the same absorbent tube; indeed the contacts between absorbent tubes of each conductor would create a closed circuit which would inductively charge the circuit of the high frequency link.
• this arrangement makes it possible to twist the two conductors and to make the connection less sensitive to electromagnetic pollution.
• FIG. 7 shows how a modulation cable 7 according to the invention will be advantageously produced with two copper wires 71 and 74 each covered with a layer of hot-deposited enamel 72 and 73, placed in an absorbent tube 75 of plastic loaded with carbon particles.
• This absorbent tube may advantageously be brought to a potential greater than ten to one hundred volts at the maximum value of the maximum potential of the conductors 71 and 74 or to a potential less than ten to one hundred volts at the maximum value of the minimum potential of the conductors 71 and 74.
• the wires 71 and 74 may have a diameter of 0.5 mm and the absorbing tube an outside diameter of 1 mm and a thickness of 1 mm.
• FIG. 8 shows how an armored modulation cable 8 according to the invention will be advantageously produced with two copper wires 71 and 74 each covered with a layer of hot-deposited enamel 72 and 73, placed in an absorbent tube 75 plastic material loaded with carbon particles, itself isolated externally by an insulator 76 and surrounded by a shield 77.
• the absorbent tube 75 and the polarization shield 77 are separated by an insulator 76 and can be brought to different potentials so as to polarize the insulators 72, 73 and 76 by at least ten to one hundred volts.
• the wires 71 and 74 can have a diameter of 0.5 mm
• the absorbent tube has an outside diameter of 7 mm and a thickness of 1 mm
• the insulation 76 has a thickness of 0.5 mm
• the shield 77 can be made of wire 0.3 mm braided bare copper. It should be noted that provision can also be made for the polarization shield 77 to be isolated from the absorbent tube 75 by the use of individually insulated wires.
• FIG. 9 shows how a power cable 9 according to the invention will be advantageously produced, by connecting in parallel several copper wires 91-98 each covered with hot-laid enamel 101-108, placed in an insulating tube 75 of plastic loaded with carbon particles.
• the threads can be arranged in a so-called "Litz thread" configuration so as to reduce the skin effect.
• the wires can be 10 in number and can have a diameter of 0.5 mm, the absorbent tube having an outside diameter of 7 mm and a thickness of 1 mm.
• This shielded power cable 10 can have an internal structure equivalent to that which has just been described with reference to FIG. 8, and also be provided with: a polarization shield 77 separated from the absorbent tube 75 by an insulating layer 76 or by the use of individually insulated wires.

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• Communication Cables (AREA)
• Insulated Conductors (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9506557

Family Applications (1)

Country Status (5)

Family Cites Families (2)

• 1997
  • 1997-05-02 FR FR9705472A patent/FR2762921B1/fr not_active Expired - Fee Related
• 1998
  • 1998-04-29 DE DE69831488T patent/DE69831488T2/de not_active Expired - Lifetime
  • 1998-04-29 WO PCT/FR1998/000867 patent/WO1998050925A1/fr active IP Right Grant
  • 1998-04-29 EP EP98922900A patent/EP0979517B1/de not_active Expired - Lifetime
  • 1998-04-29 JP JP54777298A patent/JP2001523382A/ja active Pending

Non-Patent Citations (1)

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