High speed data cable with shield connection
A high speed cable with terminating assemblies at the respective ends of the cable includes a ground wire, one or more signal wires, and a conductive layer enclosing the ground wire and the signal wires. The ground wire as well as the signal wires and the conductive layer extend into the terminating assemblies, in each of which corresponding inductive elements are coupled between the conductive layer and the ground wire. In each terminating assembly, the ground wire is shunted to the conductive layer by inductive elements, thus providing added low frequency connectivity in the cable, while at the same time blocking high frequency noise energy that may be present in the ground wire and preventing it from being coupled into, and transmitted through, the conductive layer.
1. A high speed cable, having a raw cable having a first end and a second end, and a first and second terminating assemblies at the first and second ends of the raw cable respectively, the high speed cable comprising:
a ground wire;
a signal wire; and
a conductive layer enclosing the ground wire and the signal wire;
the ground wire, the signal wire and the conductive layer extending between the first and second ends and extending into the first and second terminating ends; and
first and second inductive elements coupled between the conductive layer and the ground wire in the first and second terminating assemblies respectively, wherein the first inductive element electrically couples the conductive layer with the ground wire in the first terminating assembly and the second inductive element electrically couples the conductive layer with the ground wire in the second terminating assembly, so that the conductive layer provides a conductive path in parallel with the ground wire to shunt the ground wire with the conductive layer in said terminating assemblies.
2. The high speed cable as described in claim 1 , wherein inductance values of the first and second inductive elements are substantially the same.
3. The high speed cable as described in claim 1 , wherein inductance values of the first and second inductive elements are selected so as to provide resistance, which is noticeably greater than resistance of the ground wire at electromagnetic frequencies of interest.
4. The high speed cable as described in claim 1 , wherein the first and second inductive elements are one or more of the following:
an inductor;
a ferrite bead.
5. The high speed cable as described in claim 1 , wherein the first and second inductive elements have inductance values selected from following:
60 nH;
from about 30 nH to about 300 nH.
6. The high speed cable as described in claim 4 , wherein the inductor comprises an inductor formed on a printed circuit board (PCB) in one of the following ways:
mounted on the PCB;
implemented directly as tracks on the PCB.
7. The high speed cable as described in claim 1 , wherein the conductive layer is a shield, comprising one of the following:
a conductive braid;
a conductive foil;
a conductive braid and a conductive foil.
8. The high speed cable as described in claim 1 , further comprising a power wire enclosed by the conductive layer.
9. The high speed cable as described in claim 8 , wherein:
the power wire has a diameter, which is larger than a diameter of the ground wire; or the power wire has a diameter, which is substantially the same as a diameter of the
ground wire; or
a diameter of the signal wire is substantially the same as the diameter of the ground wire.
10. The high speed cable as described in claim 8 , wherein:
the power wire is disposed approximately in a center of the conductive layer;
the ground wire comprises two or more ground wires;
the signal wire comprises two or more signal wires; and
the signal wires is disposed in a space between the conductive layer and the power conductor and separated by the ground wires.
11. The high speed cable as described in claim 8 , wherein a diameter of the power wire and a diameter of the ground wire are specified approximately by American Wire Gauge (AWG) 22 and 36 respectively.
12. The high speed cable as described in claim 1 , wherein the signal wires comprise one or more of the following:
a shielded twisted pair (STP);
an unshielded twisted pair (UTP).
13. The high speed cable as described in claim 1 , the high speed cable being one of the following:
a Universal Serial Bus (USB) 3.0 cable;
a High-Definition Multimedia Interface (HDMI) cable.
14. The cable as described in claim 1 , wherein the signal wire is shielded in a coaxial structure having a shield.
15. The cable as described in claim 14 , wherein the shield of the coaxial structure is one of the following:
the ground wire;
a power wire.
16. The cable as described in claim 14 , wherein the conductive layer is an outer concentric conductive layer: and the cable further comprising an inner concentric conductive layer within the outer concentric conductive layer, which is insulated from the outer concentric conductive layer, wherein the inner concentric conductive layer is a power wire.
17. The cable as described in claim 16 , wherein the signal wire comprises:
at least one shielded twisted pair (STP); and
at least one insulated signal wire shielded in an individual coaxial structure.
18. A method for forming a cable having first and second ends, the cable having a ground wire and a conductive layer enclosing the ground wire, the ground wire and the conductive layer extending between the first and second ends, the method comprising:
reducing resistance of the ground wire in the cable as measured between the ends of the cable comprising:
coupling the ground wire and the conductive layer via first and second inductive elements at the first and second ends respectively, wherein the first inductive element electrically couples the conductive layer with the ground wire at the first end and the second inductive element electrically couples the conductive layer with the ground wire at the second end, so that the conductive layer provides a conductive path in parallel with the mound wire to shunt the ground wire with the conductive layer.
19. A cable having first and second ends, the cable comprising:
a ground wire;
a conductive layer enclosing the ground wire;
the ground wire and the conductive layer extending between the first and second ends of the cable;
first and second inductive elements coupled between the conductive layers and the ground wire at the first and second ends respectively, wherein the first inductive element electrically couples the conductive layer with the ground wire at the first end and the second inductive element electrically couples the conductive layer with the ground wire at the second end, so that the conductive layer provides a conductive path in parallel with the ground wire to shunt the ground wire with the conductive layer.
20. The cable as described in claim 19 , wherein inductance values of the first and second inductive elements are selected so as to provide resistance, which is noticeably greater than resistance of the ground wire at electromagnetic frequencies of interest.