Data cable for high-speed data transmissions
A data cable for high-speed data transmissions includes at least one wire pair formed of wires extending in a longitudinal direction and being surrounded by a shielding foil to form a pair shielding. A dielectric intermediate film or foil having a varying lay length is spun around the wire pair between the shielding foil and the wire pair, in order to effectively avoid a damping peak at high transmission frequencies.
1. A data cable for high-speed data transmissions, the data cable comprising:
at least one wire pair, each wire pair being formed of two wires extending in a longitudinal direction;
at least one shielding foil, each shielding foil surrounding a respective wire pair to form a pair shielding; and
at least one dielectric intermediate film, each dielectric intermediate film being spun around a respective wire pair as an additional film between said shielding foil and said wire pair, said dielectric intermediate film being spun around said wire pair with a varying length of lay.
2. The data cable according to claim 1 , wherein said length of lay varies at least within a range of +/−5% relative to a mean length of lay.
3. The data cable according to claim 1 , wherein said length of lay varies at least within a range of at least up to +/−10% relative to a mean length of lay.
4. The data cable according to claim 1 , wherein said intermediate film has a mean length of lay lying within a range of a few millimeters.
5. The data cable according to claim 1 , wherein said intermediate film has a mean length of lay lying within a range of from 5 mm to 15 mm.
6. The data cable according to claim 1 , wherein said intermediate film has a mean length of lay amounting in particular standards to approximately 6 mm to 8 mm.
7. The data cable according to claim 1 , wherein said length of lay varies uniformly in said longitudinal direction.
8. The data cable according to claim 1 , wherein said length of lay varies periodically in said longitudinal direction with a period length lying within a range of a few meters.
9. The data cable according to claim 1 , wherein said length of lay varies periodically in said longitudinal direction with a period length lying within a range of from 1 m to 5 m.
10. The data cable according to claim 1 , wherein said length of lay varies periodically in said longitudinal direction with a period length of 2 m.
11. The data cable according to claim 1 , which further comprises a further outer film spun around said pair shielding.
12. The data cable according to claim 11 , wherein said further outer film has a varying length of lay.
13. The data cable according to claim 1 , wherein said further outer film is an adhesive.
14. The data cable according to claim 1 , wherein said at least one dielectric intermediate film is spun around said at least one wire pair with a length of lay being different than a length of lay of said at least one shielding foil.
15. The data cable according to claim 1 , wherein said at least one shielding foil and said at least one dielectric intermediate film are spun around said at least one wire pair with opposite-sense lays.
16. The data cable according to claim 1 , wherein said at least one shielding foil is spun around said at least one wire pair with a constant length of lay.
17. The data cable according to claim 1 , wherein said at least one shielding foil is at least one longitudinally folded foil.
18. The data cable according to claim 1 , wherein said at least one shielding foil has a multilayered structure with an insulating backing layer and a conductive layer attached to said insulating backing layer.
19. The data cable according to claim 1 , wherein a course of a feed of a high-frequency data signal within a GHz range, at least within a frequency band up to 25 GHz, causes no signal peak to occur either in an insertion loss or in a return loss.