Low-Noise Cable

• US 20110243255A1
• Filed: 02/04/2011
• Published: 10/06/2011
• Est. Priority Date: 04/05/2010
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: PAOLETTI, Umberto
• Granted Patent: US 8,791,364 B2
• Time in Patent Office: Days
• US Class Current: 375/257
• CPC Class Codes: H01P 1/202 Coaxial filters cascaded coaxial cavities H01P1/205
• CPC Class Codes: H01P 3/06 Coaxial lines

Abstract

Methods and apparatus for reducing the electromagnetic interference (EMI). The present invention is aimed at the reduction of the electric current flowing on the external surface of shields of cables made by a combination of shielded cables. In one embodiment the cable shields are electrically connected with each other in one or a plurality of positions along the cable, in order to reduce the current flowing on the cable shields, and a conducting connection externally to the jacket is provided, in order to connect an EMI filter. In a different embodiment the cable jacket is partially removed, in order to provide an electrical connection between all the shields and an external EMI filter. In a different embodiment the cable comprises quarter-wavelength sleeve chokes in order to reduce the shield common mode current at some particular frequencies.

Claims

1. A low-noise cable comprising:

a shielded cable having an internal conductor covered by an insulator which is wrapped by a conductive cable shield and outside the cable shield is covered by a cable insulator; and

a conducting filter support,

wherein the conducting filter support is connected to the cable shield and extends outside the cable insulator.

13. An electrical equipment comprising:

a first electrical equipment; and

a second electrical equipment,

wherein said first electrical equipment and said second electrical equipment are connected by the low-noise cable as defined by claim 1.

14. An electrical equipment according to claim 13, wherein said first electrical equipment is a controlling and/or processing unit and said second electrical equipment is an input/output interface controller.

15. An electrical equipment according to claim 13, wherein said first electrical equipment is a storage memory and said second electrical equipment is an input/output interface and/or interface controller.

2. A low-noise cable comprising:

a shielded cable having plural internal conductors which are covered by insulators and said insulators are wrapped with conductive cable shields and outside the conductive cable shields are covered by a cable insulator; and

a conducting filter support,

wherein the conducting filter support is connected to at least one of the cable shields and extends outside the cable insulator.

5. A low-noise cable according to claim 2, further comprising a filter which reduces electromagnetic interference, wherein said filter is a quarter-wavelength sleeve choke which covers said shielded cable, said quarter-wavelength sleeve choke including:

a sleeve choke insulator which wraps the cable insulator; and

a conductive sleeve choke shield which covers the sleeve choke insulator.

6. A low-noise cable according to claim 5, wherein said conductive sleeve choke having a length about a quarter-wavelength of a wavelength applied to the internal conductors.

7. A low-noise cable according to claim 5, wherein said sleeve choke insulator has a large dielectric constant than the cable insulator.

8. A low-noise cable according to claim 5, wherein said sleeve choke insulator is longer than said conductive sleeve choke shield.

16. An electrical equipment comprising:

a first electrical equipment; and

a second electrical equipment,

wherein said first electrical equipment and said second electrical equipment are connected by the low-noise cable as defined by claim 2.

17. An electrical equipment according to claim 16, wherein said first electrical equipment is a controlling and/or processing unit and said second electrical equipment is an input/output interface controller.

18. An electrical equipment according to claim 16, wherein said first electrical equipment is a storage memory and said second electrical equipment is an input/output interface and/or interface controller.

3. A low-noise cable comprising:

a shielded cable having plural internal conductors each covered by a insulator; and

a conducting filter support,

wherein said insulators covering said plural internal conductors are wrapped with conductive cable shield and said conductive cable shield is covered by a cable insulator; and

wherein the conducting filter support is connected to said conductive cable shield and extends outside the cable insulator.

4. A low-noise cable according to claim 3, wherein some of said plural internal conductors each covered by said insulator are wrapped with an internal conductive shield.

9. A low-noise cable according to claim 3, further comprising a filter which reduces electromagnetic interference, wherein said filter is a quarter-wavelength sleeve choke which covers said shielded cable, said quarter-wavelength sleeve choke including:

a sleeve choke insulator which wraps the cable insulator; and

a conductive sleeve choke shield which covers the sleeve choke insulator.

10. A low-noise cable according to claim 9, wherein said conductive sleeve choke having a length about a quarter-wavelength of a wavelength applied to the internal conductors.

11. A low-noise cable according to claim 9, wherein said sleeve choke insulator has a large dielectric constant than the cable insulator.

12. A low-noise cable according to claim 9, wherein said sleeve choke insulator is longer than said conductive sleeve choke shield.

19. An electrical equipment comprising:

a first electrical equipment; and

a second electrical equipment,

wherein said first electrical equipment and said second electrical equipment are connected by the low-noise cable as defined by claim 3.

20. An electrical equipment according to claim 19, wherein said first electrical equipment is a controlling and/or processing unit and said second electrical equipment is an input/output interface controller.

21. An electrical equipment according to claim 19, wherein said first electrical equipment is a storage memory and said second electrical equipment is an input/output interface and/or interface controller.